Need to Know- Test #3

Question 1

What is the interval?

Answer 1

(LB,UB)

Question 2

What does this mean? μ

Answer 2

population mean

Question 3

What does this mean? p

Answer 3

population proportion

Question 4

What is the confidence interval?

Answer 4

We are confident the population mean OR the population proportion lies inside the internal

Question 5

What does this mean? α

Answer 5

Significance level

Question 6

What is a point estimate?

Answer 6

A point estimate is a single value used to estimate an unknown population parameter. p̂ for population proportion and x̄ for population mean

Question 7

What is the symbol for Margin of Error?

Answer 7

E

Question 8

What are the critical values?

Answer 8

z* and t*

Question 9

What is the margin of error?

Answer 9

The half-width of a confidence interval

Question 10

How do you find a confidence interval?

Answer 10

point estimate +/- margin of error

Question 11

How do you interpret the confidence interval?

Answer 11

We are [confidence level] confident the population proportion (true proportion) is between [lower bound] and [upper bound]

Question 12

What are the Conditions for Normality (population proportion)

Answer 12

1. Representative sample
2. X, the number of successes, follows a binomial distribution
3. Both np̂ and nq̂ are at least 5 (at least 5 successes and failures)

Question 13

What is the equation to work backwards given the margin of error?

Answer 13

E= UB-LB/2

Question 14

What is the equation to work backwards given the point estimate?

Answer 14

x̅ or p̂= UB+LB/2

Question 15

Which (x̅ or p̂) uses the t-distribution?

Answer 15

x̅

Question 16

How do you find degrees of freedom?

Answer 16

df= n-1

Question 17

What are the properties of the t-Distribution?

Answer 17

1. There are an infinite number of t-distributions, one for each possible value for degrees of freedom
2. The t-distribution has the same symmetric bell shape as the z-distribution, but it reflects the greater variability that is expected with estimating σ
3. The t-distribution has a mean of 0
4. The standard deviation of the t-distribution varies with the same sample size but is always greater than 1 (unlike the z)
5. As the sample size n gets larger, the t-distribution gets closer to the z-distribution

Question 18

What are the Conditions for Normality (population Mean)

Answer 18

1. Representative sample
2. The population must be normally distributed, X~normal OR The sample size needs to be large enough, n ≥ 30