Why is it not necessary to have/use a standard deviation when performing a t-test but you need one with a z-test?

If you were to add one step to better understand the five-step process, what would that be? How would it make the calculations, or process, easier?

Solution Preview

The response address the queries posted in 443 words with references.
//The given discussion paper is based on the two 'Parametric Tests', which are the't-test' and 'z-test'. In this series, in the first section of the discussion paper, the use of these two tests, in order to have the standard deviation, is explained in detail.//

Parametric test: t-test and z-test

It is not necessary to have a standard deviation while performing a t-test because the null hypothesis does not depict the true value of the standard deviation. Another crucial reason is that the population variance is not known and the sample size of the population is too small I.e. N<30it means that inferences are not normally distributed. The key reason is that the estimate ...

Solution Summary

The expert examines standard deviation when performing a t-test. The response address the queries posted in 443 words with references.

... up those number, divide by the total number of pairs (7) and you get the standard deviation! ... This will show you how to calculate means and standard deviations. ...

... Summary statistics find mean and standard deviation. ... Recall the z-value is the number of standard deviations that a value is away from the mean. ...

Expected return, standard deviation, and coefficent of variation. ... Calculate the stock's expected return, standard deviation, and coefficient of variation. ...

Control Chart and Standard Deviations. Bill Kime's bowling ball factory makes bowling balls of adult size and weight only. The standard deviation in the weight ...

Calculating Standard Deviations. ... A random sample of 100 charge account customers showed the mean age as 27 years with a standard deviation of 10 years. ...