Did you read pg. 554-569?
test statistic =
(give the formula)
test statistic = (statistic - parameter) / SD of statistic
You toss a coin 10 times to perform a test of H0: p = 0.5, HA != 0.5.
Explain why we aren't safe using a one-sample z test for the population proportion.
You toss a coin 10 times to perform a test of H0: p = 0.5, HA != 0.5.
Explain why we aren't safe using a one-sample z test for the population proportion.
Large counts condition isn't met - we can't assume normality
Is the sample range of birth weights an unbiased estimator of the population range of birth weights? Explain why or why not.
Is the sample range of birth weights an unbiased estimator of the population range of birth weights? Explain why or why not.
No, the sample range will always be less than or equal to the population range.
A large set of test scores has mean = 60 and SD = 18. If each score is doubled, then 5 is subtracted from the result, the mean and SD of the new scores will be...
a) mean: 115, SD: 31
b) mean: 115, SD: 36
c) mean: 120, SD: 6
d) mean: 120, SD 31
e) mean: 120, SD: 36
A large set of test scores has mean = 60 and SD = 18. If each score is doubled, then 5 is subtracted from the result, the mean and SD of the new scores will be...
a) mean: 115, SD: 31
b) mean: 115, SD: 36
c) mean: 120, SD: 6
d) mean: 120, SD 31
e) mean: 120, SD: 36
Explain what a test statistic measures.
Explain what a test statistic measures.
How far a sample statistic diverges from what we would expect if the null hypothesis H0 were true, in standardized units.
Explain what the Power of a significance test is.
Explain what the Power of a significance test is.
The power of a test against a specific alternative is the probability that the test will reject H0 at a chosen significance level when the specified alternative value of the parameter is true.
Assume scores on the Math SAT are roughly Normal with mean 515 and SD 114. You take an SRS of 100 students and average their SAT Math scores. You repeat this process many times. Which of the following will be equivalent to the mean and standard deviation of the sampling distribution of the sample mean?
a) mean = 515, SD = 114
b) mean = 515, SD = 114/sqrt(100)
c) mean = 515/100, SD = 114/100
d) mean = 515/100, SD = 114/sqrt(100)
Assume scores on the Math SAT are roughly Normal with mean 515 and SD 114. You take an SRS of 100 students and average their SAT Math scores. You repeat this process many times. Which of the following will be equivalent to the mean and standard deviation of the sampling distribution of the sample mean?
a) mean = 515, SD = 114
b) mean = 515, SD = 114/sqrt(100)
c) mean = 515/100, SD = 114/100
d) mean = 515/100, SD = 114/sqrt(100)
A ______ setting consists of repeated trials of the same chance process in which the probability p of success is the same on each trial, and the goal is to count the number of trials it takes to get one success.
A geometric setting consists of repeated trials of the same chance process in which the probability p of success is the same on each trial, and the goal is to count the number of trials it takes to get one success.
Following the State, Plan, Do, Conclude model, what information should be included in the State portion when explaining a hypothesis test?
Following the State, Plan, Do, Conclude model, what information should be included in the State portion?
State:
-What hypotheses you want to test
-At what significance level
-Define any parameters you use
What are 3 ways to increase the Power of a significance test?
What are 3 ways to increase the Power of a significance test?
-increase sample size
-increase significance level
-increase difference between null and alternative parameter values
Explain the different types of inference that can be made and the conditions necessary for making them.
Explain the different types of inference that can be made and the conditions necessary for making them.
Inference about a population: random selection
Inference about cause and effect: random assignment of treatments
The ______________ is the most important influence on the answers given to a sample survey.
The wording of questions is the most important influence on the answers given to a sample survey.
Following the State, Plan, Do, Conclude model, what information should be included in the Plan portion when explaining a hypothesis test?
Following the State, Plan, Do, Conclude model, what information should be included in the Plan portion when explaining a hypothesis test?
-Choose the appropriate inference method (hypothesis test)
-Check Random, Independence, and Normal conditions
According to the National Institute for Occupational Safety and Health, job stress poses a major threat to the health of workers. A news report claims that 75% of restaurant employees feel that work stress has a negative impact on their personal lives. Managers of a large restaurant chain wonder whether this claim is valid for their employees. A random sample of 100 employees finds that 68 answer “Yes” when asked, “Does work stress have a negative impact on your personal life?” Is this good reason to think that the proportion of all employees in this chain who would say “Yes” differs from 0.75? Support your answer with a significance test.
(pg. 563 from your reading)
State: H0: p = 0.75, HA != 0.75, p = true proportion of all restaurant employees at this chain who would say that work stress has a negative impact on their personal lives. significance level = 0.05
Plan: 1-sample z test for proportion. (Random sample, 100 < 10% of all employees, 100(0.75) ≥ 10, 100(0.25) ≥ 10.
Do: z = (0.68 - 0.75)/sqrt((0.75)(0.25)/100) = -1.62.
2*P(z≤ -1.62) = 0.1052
Conclude: p-value of 0.1052 > 0.05, fail to reject H0. We do not have convincing evidence that the true proportion of all employees at this restaurant chain who would say that work stress has a negative impact on their personal lives is different from 0.75.