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Determine whether the hypothesis test is one tailed or two tailed and whether to use a z-test, a t test or a X2-test.Use any method to decide whether to rejects or fail to reject the null hypothesis.
If 15 subjects take a pre-test and a post-test with a mean change score of 1.5, and if the standard deviation of the comparison distribution is calculated to be .5, what is the t score?
a researcher would like to test the claim that 9 out of 10 doctors prefer brand x. A sample of 60 doctors is obtained and each is asked to compare Brand x with another leading brand. The data show t
Records show that 116 of 115 students that studied for more than one hour received a c+ or above on the final. Use a .05 significance level to test the professor's claim.
When people smoke, the nicotine they absorb is converted to cotinine, which can be measured through blood tests. A random sample of 40 smokers has a mean cotinine level of 172.5 ng/ml. A
A new chewing gum has been developed that is helpful to those who want to stop smoking. If 60 percent of those people chewing the gum are successful in stopping smoking, what is the probability that
In any given month, the probability that a manufacturer will have an accident is 35%, What is the probability that in a 6 month period, the manufacturer will have two or fewer accident free months?
Assume that the population follows the normal distribution.Twenty trucks are randomly selected and weighed. Within what limits will 99 percent of the sample means occur?
what is the probability that the percentage in the sample will deviate from the population percentage by no more than 7 percentage points?
Twenty percent of all students who sit for the CPA exam pass it on the first time. If a random sample of 500 students sit for an exam find the probability that 18% to 23% of the students in the sam
The mean numbers of trials to learn maze for the group with the colrful wallpaper is 11. What is the standard deviation of the distribution of means?
Construct a 95% confidence interval estimate of the difference in kilometers per liter. Do the results of parts (a) and (b) agree? Explain why or why not.
Construct a 90 percent confidence interval for the proportion of all kernels that would not pop.
A company produces a women's bowling ball that is supposed to weigh exactly 14 pounds. What is the upper limit of the 95% interval? Give your answer to three decimal places.
Records show that the probability of seeing a hawk migrating on a day in September is about 35%. What is the minimal number of days a person must watch to be at least 96.8% sure of seeing one or mor
You wish to construct a 90% confidence interval for the population proportion, p, in order to test the claim from a confidence interval point of view.
What sample size is necessary for a study to determine the average cost of a child delivered at a local hospital within the past three months?
A law enforcement agent blieves that 88% of drivers stopped on weekenbd nights are given tickets. In a sample of 180 drivers, 144 were given tickets. Would this indicate that the actual proportion o
A study of vending machines that currently accept both cash and credit/debit cards compared the average purchase using credit/debit ($2.75) to the average purchase using cash ($1.50).
The quality control engineer has been checking the output by almost continuous sampling since the abnormal condition began. What is the probability that in a sample of 10 pieces.
A state meat inspector in Iowa has been given the assignments of estimating the mean net weight of packages of ground chick labeled "3 pounds." Of course he realizes that the weights cannot be preci
For 26 younger men the sample standard deviation was 84.2 mg/L. At the .01 level of significance, do these data support the conclusion that the ferritin distribution in elderly men has a smaller var
what is the probability of getting a sample proportion this small or smaller? Do you think she actually has 55% of the vote? Why or why not?
By considering the ratio P(X = x+1) / P(X=x) show that the mode of the Poisson distribution if the largest integer less than λ.
Using the confidence interval method, test the claim that the average age of consumers is at least 30 years (α= 0.05).