in which condition is a t-test used instead of a z-test? course hero

When should't-test be used instead of Z test?

When you know the population standard deviation you should use the Z-test, when you estimate the sample standard deviation you should use the T-test. Usually, we don't have the population standard deviation, so we use the T-test.

What is the main difference between the Z test and t-test?

T-test refers to a type of parametric test that is applied to identify, how the means of two sets of data differ from one another when variance is not given. Z-test implies a hypothesis test which ascertains if the means of two datasets are different from each other when variance is given.Mar 20, 2018

Under what condition is t-test used?

A t-test is a statistical test that is used to compare the means of two groups. It is often used in hypothesis testing to determine whether a process or treatment actually has an effect on the population of interest, or whether two groups are different from one another.Jan 31, 2020

Is t-test used for categorical variables?

They can be used to test the effect of a categorical variable on the mean value of some other characteristic. T-tests are used when comparing the means of precisely two groups (e.g. the average heights of men and women).Jan 28, 2020

What is the difference between T and Z distribution?

What's the key difference between the t- and z-distributions? The standard normal or z-distribution assumes that you know the population standard deviation. The t-distribution is based on the sample standard deviation.

Why are t-tests used?

A t-test is a type of inferential statistic used to determine if there is a significant difference between the means of two groups, which may be related in certain features. The t-test is one of many tests used for the purpose of hypothesis testing in statistics.

What are the conditions for a one sample t test?

Your data must meet the following requirements:Test variable that is continuous (i.e., interval or ratio level)Scores on the test variable are independent (i.e., independence of observations) ... Random sample of data from the population.Normal distribution (approximately) of the sample and population on the test variable.More items...•Apr 4, 2022

What are the conditions for T distribution?

When to Use the t Distribution The population distribution is symmetric, unimodal, without outliers, and the sample size is at least 30. The population distribution is moderately skewed, unimodal, without outliers, and the sample size is at least 40. The sample size is greater than 40, without outliers.