Hypothesis Testing Concepts

The video tutorial explains the differences between Z and T tests in hypothesis testing. It highlights when to use each test based on sample size and population variance. Two exercises are provided: one on the average lifetime of females in the US, using a Z test, and another on gasoline prices in the Midwest, using a T test. The tutorial guides viewers through setting up null and alternative hypotheses, determining critical values, and deciding whether to reject the null hypothesis based on calculated test statistics.

When should you use a Z test instead of a T test?

• When the sample mean is unknown

• When the sample size is 30 or more

• When the population variance is unknown

• When the sample size is less than 30

In the Z test example, what was the null hypothesis?

• The average lifetime of females is 75 years

• The average lifetime of females is less than 75 years

• The average lifetime of females is unknown

• The average lifetime of females is more than 75 years

What is the significance of the critical value in hypothesis testing?

• It determines the sample size

• It marks the boundary of the rejection region

• It is the same as the sample mean

• It is used to calculate the sample variance

In the Z test example, what was the calculated Z value?

• 2.49

• 1.96

• 1.43

• 0.025

What does it mean if a test statistic falls outside the rejection region?

• The test is inconclusive

• The null hypothesis is rejected

• The null hypothesis is accepted

• The null hypothesis is not rejected

In the T test example, what was the null hypothesis?

• The gasoline price is less than $2.45

• The gasoline price is $2.45

• The gasoline price is more than $2.45

• The gasoline price is unknown

Why was a T test used in the gasoline price example?

• The sample mean was unknown

• The population variance was known

• The sample size was less than 30

• The sample size was more than 30

What is the formula to calculate degrees of freedom in a T test?

• Sample size divided by two

• Sample size minus one

• Sample size plus one

• Sample size times two

In the T test example, what was the calculated T value?

• 2.49

• 2.86

• 1.96

• 0.01

What does a one-tailed test indicate in hypothesis testing?

• The test statistic can be on either side

• The test statistic is only on one side

• The test statistic is always positive

• The test statistic is not used