isds chapter 9 exam 3

"I am going to get the majority of the votes to win this election."

H0: p ≤ 0.50; HA: p > 0.50

if i dont know the standard deviation

0.065−0.081/ 0.081×(1−0.081)/√1000

significance level

100a%

two-tailed test

when the alternative hypothesis includes the =/ (not equal) sign. if the null hypothesis is rejected it suggests that the true parameter does not equal the hypothesized value

what happens if you try to reduce the likelihood of one type of error from occurring?

will increase the likelihood of the other error.

whats wrong H0: X¯ ≤ 128; HA: X¯ > 128

hypothesis testing is about a population parameter not a sample statistic

when do you reject the null hypothesis?

if sample evidence is inconsistent with the null hypothesis

when do you not reject the null hypothesis?

if sample evidence is not inconsistent with the null hypothesis or when the observed probability of a type 1 error is less than than the allowed probability fo a type 1 error

A company has developed a new diet that it claims will lower one's weight by more than 10 pounds. Health officials decide to conduct a test to validate this claim. The consumers should be

more concerned about Type I error

one-tailed test

null hypothesis that can only be rejected on one side of the hypothesized value. greater or less than.

type 1 error

Rejecting null hypothesis when it is true

null hypothesis

corresponds to a presumed default state of nature or status quo.

type 2 error

failing to reject a false null hypothesis

whats wrong H0: μ ≤ 10; HA: μ ≥ 10

the alternative hypotheses ha should not have equality sign

whats wrong H0: μ ≠ 500; HA: μ = 500

the alternative hypotheses ha should not have equality sign

how to find p value in excel?

=1-NORM.DIST(z value, 0,1,TRUE)

"I will have to fine the company since its tablets do not contain an average of 250 mg of ibuprofen as advertised."

H0: μ = 250; HA: μ ≠ 250

"I suspect that your 10-inch pizzas are, on average, less than 10 inches in size."

H0: μ ≥ 10; HA: μ < 10

The owner of a large car dealership believes that the financial crisis decreased the number of customers visiting her dealership. The dealership has historically had 800 customers per day. The owner takes a sample of 100 days and finds the average number of customers visiting the dealership per day was 750. Assume that the population standard deviation is 350. To determine whether there has been a decrease in the average number of customers visiting the dealership daily, the appropriate hypotheses are

H0:μ≥800,HA:μ<800

alternative hypothesis

contradicts the default state or status quo

Consider the following competing hypotheses: H0:μ = 0, HA:μ ≠ 0. The value of the test statistic is z = −1.38. If we choose a 5% significance level, then we

do not reject the null hypothesis and conclude that the population mean is not significantly different from zero

A newly hired basketball coach promised a high-paced attack that will put more points on the board than the team's previously tepid offense historically managed. After a few months, the team owner looks at the data to test the coach's claim. He takes a sample of 36 of the team's games under the new coach and finds that they scored an average of 101 points with a standard deviation of 6 points. Over the past 10 years, the team had averaged 99 points. What is the value of the appropriate test statistic to test the new coach's claim at the 1% significance level?

t35 = 2.00 101− 99/6/√36

what does "a" mean?

the allowed probability making type 1 error

whats wrong H0: p ≤ 0.40; HA: p > 0.42

the hypothesized value is not the same under the null and alt hypotheses

p-value

the likelihood of obtained a sample mean that is at-least as extreme as the one derived from the given sample

A university is interested in promoting graduates of its honors program by establishing that the mean GPA of these graduates exceeds 4.00. A sample of 36 honors students is taken and is found to have a mean GPA equal to 4.10. The population standard deviation is assumed to equal 0.40. The parameter to be tested is

the mean gpa of the university honors students

what do you do if you do not have the population mean and standard deviation known?

the value of the test statistic is computed as n-1=df

if the null hypothesis is true what does the answer to the p value equation mean

there is a % change that the sample mean will be the average or more

If the chosen significance level is α = 0.05, then

there is a 5% probability of rejecting a true null hypothesis