When the population is not normally distributed the sampling distribution of the mean?
Probability and Statistics > Non Normal Distribution Although the normal distribution takes center stage in statistics, many processes follow
a non normal distribution. This can be due to the data naturally following a specific type of non normal distribution (for example, bacteria growth naturally follows an exponential distribution). In other cases, your data collection methods or other methodologies may be at fault. Watch the video for
an overview of non normal distributions: Can’t see the video? Click here. Types of Non Normal DistributionMany distributions naturally follow non normal patterns.
Reasons for the Non Normal DistributionMany data sets naturally fit a non normal model. For example, the number of accidents tends to fit a Poisson distribution and lifetimes of products usually fit a Weibull distribution. However, there may be times when your data is supposed to fit a normal distribution, but doesn’t. If this is a case, it’s time to take a close look at your data.
Dealing with Non Normal DistributionsYou have several options for handling your non normal data. Many tests, including the one sample Z test, T test and ANOVA assume normality. You may still be able to run these tests if your sample size is large enough (usually over 20 items). You can also choose to transform the data with a function, forcing it to fit a normal model. However, if you have a very small sample, a sample that is skewed or one that naturally fits another distribution type, you may want to run a non parametric test. A non parametric test is one that doesn’t assume the data fits a specific distribution type. Non parametric tests include the Wilcoxon signed rank test, the Mann-Whitney U Test and the Kruskal-Wallis test. See also:
ReferencesBeyer, W. H. CRC Standard Mathematical Tables, 31st ed. Boca Raton, FL: CRC Press, pp. 536 and 571, 2002. ---------------------------------------------------------------------------
Need help with a homework or test question? With Chegg Study, you can get step-by-step solutions to your questions from an expert in the field. Your first 30 minutes with a Chegg tutor is free! Comments? Need to post a correction? Please Contact Us. What if the population is not normally distributed the distribution of the sample means for a given sample size n will?Answer and Explanation:
The population is non-normal, the sampling distribution of sample means from this population will approach a normal distribution as the sample size n increases.
What does it mean if a sample is not normally distributed?Collected data might not be normally distributed if it represents simply a subset of the total output a process produced. This can happen if data is collected and analyzed after sorting.
Is the sampling distribution of the mean always normally distributed?We just said that the sampling distribution of the sample mean is always normal. In other words, regardless of whether the population distribution is normal, the sampling distribution of the sample mean will always be normal, which is profound!
When the population has a normal distribution the sampling distribution of is normally distributed?If the sampled population is exactly normal distribution, then the sampling distribution of "x bar" is also expected to be normal regardless of the sample size. If a population is known to be normally distributed, then it follows that the sample mean must equal the population mean.
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