Reference no: EM137751
1. A bank wants to get new customers for their credit card. They try two different approaches in their marketing campaign. The first promises a "cash back" reward; the second promises low interest rates. A sample of 500 people are mailed the first brochure; of these, 100 get the credit card. A separate sample of 500 people are mailed the second brochure; 125 get the credit card. Are the two campaigns equally attractive to customers? Compute a 95% confidence interval for the difference in the two proportions.
A. (0.21, 0.29)
B. (-0.102, 0.002)
C. (-0.118, 0.018)
2. Drug sniffing dogs must be 95% accurate. A new dog is being tested and is right in 46 of 50 trials. Find a 95% confidence interval for the proportion of times the dog will be correct.
A. (0.845, 0.995)
B. (0.805, 0.973)
C. (0.819, 0.959)
3. A student believes that 20% of all students think pepperoni is their favorite pizza. He performs a test of hypothesis, H0: p = 0.2, having taken a sample of 200 students and finding that 52 think pepperoni is their favorite. He finds a p-value of 0.0338, so rejects the null at α = 0.05. He then computes a 95% confidence interval for the true proportion and finds it is (0.199, 0.321). He is confused. 20% is in the interval! What is the difference?
A. He made a mistake in one of his calculations.
B. The two use different values of p in computing the standard deviation.
C. He should have used the plus four confidence interval.
|
Confidence interval estimate for the proportion
: The margin of error for a 95% confidence interval estimate for the proportion of all students with cell phones is
|
|
Find a confidence interval for the difference
: There were 3 defectives in the first batch and 5 in the second. Find a 95% confidence interval for the difference in the proportion of defectives.
|
|
Conduct a poll to discover the proportion
: how many individuals will I need to sample if I want a 95% margin of error to be no more than 3%, I want to know if the results are significant at = 10%. With the information given.
|
|
What is the estimate of the overall proportion
: We want to know if his support has decreased. In computing a test of hypothesis with , what is the estimate of the overall proportion?
|
|
Performs a test of hypothesis
: Drug sniffing dogs must be 95% accurate. A new dog is being tested and is right in 46 of 50 trials. Find a 95% confidence interval for the proportion of times the dog will be correct.
|
|
Determine - test the hypotheses
: A bank wants to get new customers for their credit card. They try two different approaches in their marketing campaign. The first promises a "cash back" reward; the second promises low interest rates. A sample of 500 people are mailed the first br..
|
|
Margin of error with confidence
: An SRS of 100 of a certain popular model car in 1993 found that 20 had a certain minor defect in the brakes. An SRS of 400 of this model car in 1994 found that 50 had the minor defect in the brakes. Let p1 and p2 be the proportion of all cars of t..
|
|
Probability that the psychic correctly identifies the symbol
: A noted psychic was tested for ESP. The psychic was presented with 400 cards face down and asked to determine if each card was marked with one of four symbols: a star, cross, circle, or square. The psychic was correct in 120 cases. Let p represent..
|
|
Determine the confidence interval
: Which of the following assumptions for inference about a proportion using a confidence interval are violated,
|