Basics of Standard Deviation: Definition, Formula and Examples

Basics of Standard Deviation: Definition, Formula and Examples

Standard deviation gives a clearer understanding of the variability of data points around the mean value as well as summarizes the overall behavior of the data. It also helps to determine trends and patterns in datasets. The abbreviation “SD” is often used to represent the standard deviation.

It is also indicated by the Greek letter sigma (σ) for the population standard deviation and the Latin letter (s) for the sample standard deviation.

In this article, we will learn more about standard deviation and formulas to find. We will cover different properties of standard deviation that help us in solving the question. We will understand how to find SD through many examples.

Just stay with us to become an expert in calculating Standard deviation.

What is Standard Deviation (SD) in the Statistics?

In statistics, a standard deviation is a measure of the dispersion or variation in given data. Standard deviation provides information on how much individual data points differ from the mean of the dataset. It calculates the degree of spread within a group of numbers.

  • Smaller standard deviations indicate that data points tend to be closer to the mean.
  • Larger standard deviations show more variations in values.

Standard Deviation (SD) can be defined mathematically as the positive square root of the average of the squared differences between each data point and the mean. Standard deviation helps in understanding how much individual data point differs from the average value, which provides insight into the spread or dispersion within the dataset.

Standard deviation Formulas for Population & Sample

The standard deviation formula allows us to find the numerical amount of dispersion or scatter within a dataset. The calculation of standard deviation involves using different formulas based on whether the dataset represents the entire population or a sample.

The formulas for standard deviation are as follows:

 Standard Deviation of Population Data

The population standard deviation formula is applied when we have data for the entire group or population and we want to measure the variability or spread of values around the population mean.

Population Standard Deviation (σ) Formula

σ = √ [Σ (xi – µ) 2 / N]

or

Shortcut methods = σ = √ [(Σ x 2 / N) – ([Σ x / N) 2]

Where:

  • σ = standard deviation for population
  • Σ = sum of …
  • xi = each value in the population
  • µ = the population mean
  • N = the population size

Sample Standard Deviation

The sample standard deviation formula is used when we are working with a subset of data rather than the entire population and we want to measure the variability or spread of values around the sample mean.

Sample Standard Deviation (s) Formula

s = √ [Σ (xi – x̄) ² / (n – 1)]

Where:

  • s = SD for the sample
  • xi = each value in the sample
  • x̄ = sample mean
  • n = sample size

Note: The major difference between the population and sample standard deviation formulas is that for the sample, we divide by (n-1) instead of N, to provide an unbiased estimator of the population standard deviation.

Common Properties of Standard Deviation

There are several properties and methods associated with calculating the standard deviation:

  • The standard deviation is always greater than or equal to zero (i.e. SD ≥ 0).
  • The standard deviation will be zero if all of the data points in the set are the same.
  • Adding or subtracting a constant from each value in the dataset does not affect its standard deviation.
  • The standard deviation can be affected if there are any extreme values in the data set.
  • The standard deviation is very helpful in identifying the shape of a distribution such as whether it is bell-shaped, skewed, or uniform.

How to Find Standard Deviation of Population and Sample?

Here are the steps to find the SD for both population and sample data:

  1. Determine the mean (average) of the given data set. (∴ Average = Sum of dataset / Number of items in the dataset).
  2. Determine the deviation of each observation from the mean of the dataset and take a square of each deviation.
  3. Sum all of the squared values obtained from step 2.
  4. Divide the sum of squared values by the total number of data points minus 1 for the population standard deviation. For sample data, divide the answer of result step 2 by the total number of data points.
  5. Now, take the positive square root to get SD.

Let us consider some examples to clarify these steps further.

Solved Examples

Example 1:

The distances covered by a runner in consecutive days are 3, 4, 5, 6, 7, 8. Calculate the standard deviation of the distances covered.

Solution:

Step One: Find the mean (average) of the distances:

Mean (or average) = x̄ = (3 + 4 + 5 + 6 + 7 + 8) / 6

= 33 / 6

x̄ = 5.5

Step Two: Determine the differences between each distance and the mean and take a square of each difference.

x (xi – x̄) (xi – x̄)2
3 3 – 5.5 = -2.5 (-2.5)2 = 6.25
4 4 – 5.5 = -1.5 (-1.5)2 = 2.25
5 5 – 5.5 = -0.5 (-0.5)2 = 0.25
6 6 – 5.5 = 0.5 (0.5)2 = 0.25
7 7 – 5.5 = 1.5 (1.5)2 = 2.25
8 8 – 5.5 = 2.5 (2.5)2 = 6.25

Step Three: Find the sum of the squared differences.

Σ (xi – x̄)2 = 6.25 + 2.25 + 0.25 + 0.25 + 2.25 + 6.25 = 17.5

Step Four: Divide the sum by the total number of distances minus 1 (since it is a sample).

[Sum of (xi – x̄) ² / (n – 1)] = 17.5 / (6 – 1)

= 17.5 / 5

= 3.5

Step Five: Calculate the positive square root of the obtained result to find the standard deviation for the sample.

Standard deviation = √ [Σ (xi – x̄) ² / (n – 1)]

= √ (3.5)

= 1.87

Thus, the standard deviation of the distances covered by the runner over consecutive days is approximately 1.87 units.

The problems of standard deviation can also be solved by using a standard deviation formula calculator to quickly find the results with steps in order to save time.

Example 2.

Compute the standard deviation for the following dataset.

8, 8, 8, 8, 8, 8

Solution:

Standard deviation = 0

Because we know that if all of the data points in the set are the same, then the standard deviation will be zero.

Conclusion

In this article, we have explored the concept of standard deviation in depth. We examined different formulas for calculating the standard deviation for both sample and population data. We discussed properties that play a vital role in solving problems.

We provided steps to find the standard deviation (SD), and to understand them practically, we solved examples in the examples section. After reading this article, you will be able to calculate SD quickly and with ease.

Learn the Basics of Critical Value: Definition, Types, and Calculation.

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What Should You Keep in Mind When Choosing Care Services for Your Family?

What Should You Keep in Mind When Choosing Care Services for Your Family?

If you’re a family member caring for elderly loved ones or looking after a disabled relative, it can be tough to know where to start when finding care services. With so many choices and the potential for unfamiliar challenges, you want to get informed and make the right decisions.

That’s why we’ve put together this guide – so that you can understand what should go into choosing quality care services from reputable organizations that will meet your needs and those of your family members.

In this blog post, we’ll help you navigate through the different types of care available, discuss financial considerations, and provide support on how best to find a trustworthy provider for your particular requirements.

Research Different Types of Care Service Providers

There are a variety of care service providers available to those seeking support for their elderly loved ones. Look for elderly home care services that specifically cater to those seeking personalized care for their aging family members. These services offer the ability for the elderly to receive care in the comfort of their own homes while still being provided with the necessary attention and support.  Alternatively, you may consider assisted living facilities or nursing homes for those who require more intensive care and assistance.

Thoroughly research each type of care service provider to determine which one will best meet the needs of your family member. Consider factors such as cost, location, services provided, and staff qualifications before taking the plunge.

Compare Each Provider

After you’ve conducted thorough research on different types of care service providers, the next step is to compare them. Make a list of potential providers and evaluate each one, taking into account your specific needs and the needs of your family members. Here are some valuable tips to keep in mind during this process:

  • Ask for references from each provider and follow up on them. Speak to previous or current clients, as well as their family members. This will give you firsthand insights into the quality of care and services provided.
  • Look into the provider’s reputation. Check online reviews and ratings, ask for recommendations from trusted sources, and research any complaints or violations.
  • Inquire about the provider’s staff qualifications and training. It’s important to ensure that those caring for your family members are properly trained and qualified to do so.
  • Consider the location, accessibility, and convenience of each provider. This is especially crucial if you or other family members will be involved in the care process.

Take the time to compare and contrast each option, and you can feel confident in your decision and ensure that you’re getting the best possible service for your senior care needs.

Ask for References From Friends and Family

Turning to people you trust for references can be extremely helpful in your search for a care service provider. Friends, family, or colleagues who have gone through a similar process can provide valuable insights and recommendations. They can share their experiences — both positive and negative — about particular providers, giving you a more personal view of the services available.

Ask them about the quality of care, the professionalism of the staff, and how the provider handled any issues or problems that arose. Their feedback can help you refine your list of potential providers, saving you time and reassuring you that you’re making the right choice for your family.

Consider Your Budget

Cost is unquestionably a significant factor when selecting a care service provider. It’s essential to have a clear understanding of your financial resources and how much you can realistically commit to care services without straining your budget. Factor in government assistance programs or insurance coverage that may be available.

Different providers have varying pricing structures for home care packages, so be sure to ask for detailed information on all costs involved. Some providers may offer a flat rate while others might charge additional fees for specific services. Most of the time, the most expensive provider doesn’t necessarily guarantee the best care. What matters is the quality of care your loved one receives. So balance cost considerations with the provider’s qualifications, reputation, and the feedback you’ve gathered from references.

Research Different Types of Care Service Providers

Look Into the Availability of Local Support Groups

Local support groups can be a treasure trove of information and emotional support when navigating the complex landscape of care services. Whether they are formed by other families who have procured care services, professionals in the field, or community-based organizations, these groups can provide advice, recommendations, and a sense of community during this challenging time. They can offer firsthand insights into local providers, assistance with financial planning, and strategies for handling the emotional aspects of securing care for a loved one.

Local support groups can even provide much-needed moral support from people who understand what you are going through. Keep in mind that reaching out for help is not a sign of weakness; it’s a step towards ensuring you’re making the best possible decisions for your family.

Choosing a care service provider for your loved ones is a personal journey that requires patience, diligence, and empathy. Although it may seem overwhelming, remember that your efforts are for the welfare of your family member who deserves the best possible care.

Do your best to gather as much information as you can, rely on the counsel of trusted friends, family, and local resources, and consider your decision carefully.

Are your parents still in their own home or perhaps living with you?

Related Reading

Home safety tips for households living with elders.
From little ones to loved ones visiting grandparents in home care.

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Creating a Safe Haven: The Role of Eco-Friendly and Non-Toxic Products In Family Homes

Creating a Safe Haven: The Role of Eco-Friendly and Non-Toxic Products In Family Homes

We can all agree that living and working in clean environments is beneficial to your health. However, the majority of home cleaners are composed of a toxic concoction. While it may be more convenient to leave the cleaning to the pros, coming home to a house scrubbed with a cocktail of harsh chemicals exposes you to the hidden risks associated with using such chemicals.

Making the move to use as many green products as you can is one of the best ways to mitigate the harm being done to the environment and prevent the numerous hazards linked with using toxic cleaning products.

Cleaning materials do not have to be hazardous to be effective and produce the intended effects. Switching to natural and eco-friendly cleaning solutions offers several advantages beyond having clean surfaces.

Here we will discuss the importance making sustainable choices and using eco-friendly cleaning products in your homes.

Non-Toxic Products Provide Better Indoor Air Quality

Most people believe that the air they breathe indoors is less polluted than the air they breathe outside. The US EPA estimates that indoor air quality is 2.5 times worse than outside air quality.

However, it is evident that the likelihood of adverse health consequences from inhaling contaminated indoor air is proportional to the number of hazardous substances in the air, as well as the time and frequency with which you are exposed.

While it is nearly impossible to eliminate chemical emissions and achieve perfect air quality, it is possible to limit exposure, improve indoor air quality by keeping the area well-ventilated, and reduce pollution sources such as smoking, heating, household products, and so on.

The products you use in your homes are one of the most common sources of poor indoor air quality and one of the easiest to eliminate.  Inhalation is the most common route of exposure for these products. Many household cleaning solutions contain inorganic compounds like ammonia as well as volatile organic compounds (VOCs) including formaldehyde, perchloroethylene, benzene, naphthalene, and nitrogen dioxide.

For example, glass cleaners, dry up quickly at normal temperatures because of evaporation. The chemical begins to circulate in the air as soon as it is sprayed, and it may produce immediate eye, nose, and throat irritation, headache, dizziness, or aggravation of asthma symptoms. If you want to make your home safer and healthier, we recommend switching to an eco-friendly glass cleaner.

Green Home Cleaners are Safer For Your Children and Pets

Toxic substances are absorbed not just by inhalation, but also through ingestion and skin absorption. Every parent keeps dangerous cleaning items out of their children’s reach and sight, yet according to the American Association of Poison Control Centers, personal care products and home cleaning compounds were the most common causes of poisoning in children aged 5 and under.

Pets, like newborns and small children, are vulnerable to home cleansers that contain dangerous chemicals. If we have a pet or children at home, it’s natural to wonder how the flooring affects them because they spend so much time playing and crawling on it. They not only touch surfaces, but they also want to taste everything, particularly their hands. Aside from respiratory consequences, frequent use of home cleaning solutions is linked to rhinitis and other allergy symptoms in children.

The good news is that natural cleaning agents do not pose such risks.

Maintains Your Belongings and Makes Them Last Longer

One of the most significant advantages of using natural cleaning solutions is their long-term impact. Traditional cleaning products frequently fail to be sustainable, meaning that harsh chemicals have a detrimental impact on the life and texture of your items.

Sink stains and buildup may be removed with abrasive cleansers. Surfaces may get stained or discolored over time since abrasiveness can permanently damage the surface. The same is true for extremely acidic house cleaning agents. Furthermore, if you accidentally spill a bit of, say, acidic toilet bowl cleaning on your clothing or carpet, it will bleach the color immediately.

Mixing different chemicals to get better cleaning performance, even if you use one chemical on top of another, not only impacts your health but is also another reason why your surfaces are more prone to damage.

Nontoxic cleaning products such as vinegar work the same way and will clean your surfaces without damaging them.

Better for the environment

Natural products are better for the environment. Toxic, non-green cleaning chemicals are also possibly harmful to the environment. When washing down the drain or evaporating volatile organic compounds, these products are discharged into the environment during routine use. People who use items containing harsh chemicals contribute directly to air and water pollution.

Many surfactants used in traditional products biodegrade slowly or transform into more hazardous, persistent, and bioaccumulative compounds, posing harm to aquatic life.

Furthermore, the manufacturing of cleaning products has an impact on the environment. When it comes to production, each country has various rules and regulations, making it impossible to know if an organization is taking good care of the harmful waste they generate.

Even though regular sewage treatment efficiently decreases or eliminates the majority of cleaning product elements in wastewater, certain cleaning product chemicals are not adequately handled. According to the EPA, alkylphenol ethoxylates, a common surfactant chemical in cleansers, cause health problems in wildlife exposed to contaminated waterways by disrupting the endocrine system. This is one of several surfactants included in conventional goods that endanger aquatic life and biodegrade slowly or into more harmful compounds.

Join the Movement Towards Safer, Healthier Homes

In conclusion, the shift to eco-friendly and non-toxic products in our homes is more than a trend; it’s a necessary move toward ensuring the health and safety of our families. Companies like Melaleuca have shown that it’s possible to have effective, affordable products without compromising on safety or environmental impact.

Melaleuca’s commitment to non-toxic, safe products is evident in their rigorous testing and research. They focus on using natural ingredients that are effective yet gentle, ensuring that every product is suitable for family use.

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When Your Child Should See a GP: Recognizing the Signs of Health Concerns

When Your Child Should See a GP: Recognizing the Signs of Health Concerns

As a parent, your child’s health and well-being are among your top priorities. While children can experience occasional minor illnesses, recognizing when it’s time to visit to a general practitioner (GP) is necessary. Understanding the signs of health concerns and knowing when to seek medical attention ensures your child’s continued health and development.

It is our desire to support you as a parent for your own peace of mind, but more importantly, your child’s well-being.  We are not health professionals. You should always consult your local health authorities before prescribing unknown remedies or over the counter medications. With that being said, we did a little research to explore when your child should see a GP and provide guidance on recognizing the signs of potential health issues.

1. Persistent Fever

Fever is a common symptom in children and is often caused by viral infections. However, if your child’s fever persists for more than a few days, is very high (above 104°F or 40°C), or is accompanied by other concerning symptoms, such as lethargy, difficulty breathing, or a rash, then it’s time to consult a GP. A persistent fever may indicate a more significant underlying issue that requires medical evaluation.

2. Skin Abnormalities

Skin issues in children, such as persistent rashes, hives, or unusual growths, may require medical attention. Some skin conditions can be indicative of allergies, infections, or underlying medical conditions. If you notice any concerning changes in your child’s skin, consult with a GP at TapGP for an evaluation.

3. Unexplained Pain

Persistent or unexplained pain in children should be addressed by a medical professional. Whether it’s abdominal pain, headaches, joint pain, or any other type of discomfort, consult with a GP to determine the cause and get appropriate treatment.

4. Behavioral and Developmental Concerns

Behavioral and developmental concerns in children shouldn’t be overlooked. If you notice significant changes in your child’s behavior, mood, or developmental milestones, it may be advisable to consult with a GP. Conditions such as attention deficit hyperactivity disorder (ADHD) or developmental delays may require early intervention for better outcomes.

5. Frequent Infections

If your child frequently experiences ear infections, throat infections, or urinary tract infections, it may be a sign of an underlying issue. A GP can assess your child’s immune system and overall health to identify potential contributing factors.

6. Growth and Weight Concerns

Significant changes in your child’s growth, weight, or appetite can be indicative of underlying health concerns. Consult a GP if you have concerns about your child’s growth trajectory or if they exhibit sudden or unexplained changes in appetite or weight.

7. Mental Health and Emotional Issues

Good mental health and emotional well-being are vital for children’s overall development. If you notice signs of anxiety, depression, extreme mood swings, or behavioral problems in your child, it’s essential to consult with a GP. They can provide guidance, referrals, or interventions to support your child’s mental health.

8. Routine Check-ups and Vaccinations

Regular well-child checkups with a GP are crucial for monitoring your child’s growth and development. These visits also ensure that your child receives the recommended vaccinations and preventive care to maintain good health.

In conclusion, recognizing when your child should see a GP is vital for ensuring their health and well-being. While some symptoms may resolve on their own, persistent or severe signs of health concerns shouldn’t be ignored.

Consulting with a GP in a timely manner can help diagnose and address potential issues, provide appropriate treatment, and support your child’s long-term health and development. Remember that early intervention and proactive healthcare are key to helping your child thrive.

Read how to choose the best pediatrician for your child.

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