IA2

Question 1

What are the similarities between a t-distribution and a Normal distribution?

Answer 1

Both are symmetric and unimodal.

Question 2

What are the 4 conditions for a binomial distribution?

Answer 2

Binary (success/failure) Independent Number of trials is fixed Same success (probability of success is the same)

Question 3

When are results statistically significant?

Answer 3

When the p-value is greater than alpha, or 0.05, if no significance level is set by the problem.

Question 4

What is the relationship between the standard deviation of a population and the mean of the sampling distribution of x-bar?

Answer 4

The standard deviation of the sampling distribution of x-bar will always be smaller.

Question 5

How do you find degrees of freedom?

Answer 5

df = n-1

Question 6

What is a t-distribution?

Answer 6

The t distribution distribution that is used to estimate population parameters when population variance/standard deviation is unknown (when we use the sample variance/standard deviation instead)

Question 7

What conditions must be checked in order to show that the sampling distribution of x-bar is approximately Normal?

Answer 7

The sample size must be greater than 30 or the population must be Normally distributed.

Question 8

What is the relationship between the mean of a population and the mean of the sampling distribution of x-bar?

Answer 8

They are the same.

Question 9

What happens to the width of a confidence interval when you increase the sample size?

Answer 9

The confidence interval becomes narrower.

Question 10

What does it mean for test results to be statistically significant?

Answer 10

Statistically significant means that the results were not likely to happen by chance.

Question 11

What is the name of the procedure we use to construct a confidence interval for the population mean?

Answer 11

One sample t interval for miu

Question 12

What happens to the width of a confidence interval when you increase the confidence level?

Answer 12

The confidence interval becomes wider.

Question 13

What is expected value referring to?

Answer 13

The mean of a random variable.

Question 14

What are the three conditions required to construct a confidence interval for p?

Answer 14

Random, 10%, Normal

Question 15

How do you check for Normality when constructing a confidence interval for miu?

Answer 15

The sample size must be greater than 30 or the population must be Normally distributed.

Question 16

What conditions must be checked in order to calculate the standard deviation of the sampling distribution of x-bar?

Answer 16

10% condition

Question 17

What happens to the width of a confidence interval when you decrease the confidence level?

Answer 17

The confidence interval becomes narrower.

Question 18

What makes a t-distribution different from a Normal distribution?

Answer 18

The t-distribution has more variability than a Normal distribution. It has more area in the tails.

Question 19

How do you check for Normality when constructing a confidence interval for p?

Answer 19

n*p-hat is greater than or equal to 10 n(1-p-hat) is greater than or equal to 10

Question 20

What is the margin of error?

Answer 20

The margin of error is the maximum expected difference between the statistic and the parameter.

Question 21

What happens to the width of a confidence interval when you decrease the sample size?

Answer 21

The confidence interval becomes wider.

Question 22

What is the name of the procedure we use to construct a confidence interval for the population proportion?

Answer 22

One sample z interval for p.

Question 23

What are the three conditions required to construct a confidence interval for miu?

Answer 23

Random, independent, Normal

Question 24

How do degrees of freedom/sample size impact the shape of a t-distribution?

Answer 24

As the sample size/degrees of freedom increase, the t-distribution get closer to a Normal distribution.