Question

Question 11

Item 11

A study was conducted to investigate whether the mean numbers of snack bars sold at two airport convenience stores, C and D, were different. For ten randomly selected days, the number of snack bars sold at each store was recorded, and the sample mean number of snack bars for each store was calculated. A two-sample tt-test for a difference in means will be conducted.

Have all conditions for inference been met?

• Yes, all conditions have been met.

  A

• No, the data were not collected using a random method.

  B

• No, the sample sizes are greater than 10 percent of the population.

  C

• No, the sample sizes are not large enough to assume normality of the sampling distribution.

  D

• No, the distribution of the population is known to be skewed.

  E

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Answer 1

Option(C): No, the sample sizes are not large enough to assume normality of the sampling distribution.

>> To conduct a two sample t test, the population distributions must be normal from where the sample was taken. As, we do not know the shape of population distributions here, the sample sizes must be greater than 30 to ensure that the shape of the sampling distributions are approximately normal (central limit theorem).