Question

1.  

Determine the area under the standard normal curve that lies to the right of

z = -.22 z = .29 c = 1.05 and d = -.97

2.

A​ bank's loan officer rates applicants for credit. The ratings are normally distributed with a mean of 200 and a standard deviation of 50. If an applicant is randomly​ selected, find the probability of a rating that is between 200 and 275. Round your answer to four decimal places.

3.

The serum cholesterol levels for men in one age group are normally distributed with a mean of 178.2

and a standard deviation of 40.5. All units are in​ mg/100 mL. Find the 9th percentile. Round your answer to the nearest tenth as needed.

4.

Given below are the number of successes and sample size for a simple random sample from a population.

x=8​,

n= 50​,

90% level

a. Determine the sample proportion.

b. Decide whether using the​ one-proportion z-interval procedure is appropriate.

c. If​ appropriate, use the​ one-proportion z-interval procedure to find the confidence interval at the specified confidence level.

d. If​ appropriate, find the margin of error for the estimate of p and express the confidence interval in terms of the sample proportion and the margin of error.

5.

Use the​ one-proportion z-interval procedure to find the required confidence interval.

When 272 college students are randomly selected and​ surveyed, it is found that

112 own a car. Find a​ 99% confidence interval for the proportion of all college students who own a car.

6.

A philanthropic organisation sent free mailing labels and greeting cards to a random sample of 100,000

potential donors on their mailing list and received 5116 donations.

​(a) Give a 90% confidence interval for the true proportion of those from their entire mailing list who may donate.

​(b) A staff member thinks that the true rate is 5.1​%.

Given the confidence interval you​ found, do you find that rate​ plausible?

7.

The test statistic in a two-tailed two test is z =−1.89.

Determine the​ P-value and decide​ whether, at the 5% significance​ level, the data provide sufficient evidence to reject the null hypothesis in favor of the alternative hypothesis.

8.

The significance level and​ P-value of a hypothesis test are given. Decide whether the null hypothesis should be rejected.

α = 0.01 P-value - 0.007

9.

Find the​ P-value for the indicated hypothesis test.

In a sample of 47 adults selected randomly from one​ town, it is found that 9 of them have been exposed to a particular strain of the flu. Find the​ P-value for a hypothesis test to determine whether the proportion of all adults in the town that have been exposed to this strain of the flu differs from​ 8%.

10.

According to a publication 13.4% of 18 to 25 year olds were using marijuana in 2000. A recent poll of 1235 randomly selected 18 to 25 year olds revealed that 184 currently use marijuana. At the 10% significance level, does the data provide sufficient evidence to conclude that the percentage of 18 to 25 year oldsw ho currently use marijuana has changed from the 2000 percentage of 13.4%?

Use the​ one-proportion z-test to perform the appropriate hypothesis​ test, after checking the conditions for the procedure.

Answer 1