Reference no: EM137747
1. An inspector inspects large truckloads of potatoes to determine the proportion p with major defects prior to using the potatoes to be made into potato chips. She intends to compute a 95% confidence interval for p. To do so, she selects an SRS of 50 potatoes from the over 2000 potatoes on the truck. Suppose that only 2 of the potatoes sampled are found to have major defects. Which of the following assumptions for inference about a proportion using a confidence interval are violated?
A. The population is at least 10 times as large as the sample.
B. n is so large that both the count of successes n and the count of failures n (1 - ) are 10 or more.
C. There appear to be no violations.
2. An inspector inspects large truckloads of potatoes to determine the proportion p in the shipment with major defects prior to using the potatoes to make potato chips. Unless there is clear evidence that this proportion is less than 0.10 she will reject the shipment. To reach a decision she will test the hypotheses
H0: p = 0.10, Ha: p < 0.10
using the large sample test for a population proportion. To do so, she selects an SRS of 50 potatoes from the over 2000 potatoes on the truck. Then
A. the Normal approximation to the binomial can safely be used for this significance test.
B. the Normal approximation to the binomial should not be used for this significance test.
C. the alternative hypothesis should be Ha: p > 0.10.
3. 100 rats whose mothers were exposed to high levels of tobacco smoke during pregnancy were put through a simple maze. The maze required the rats to make a choice between going left or going right at the outset. 80 of the rats went right when running the maze for the first time. Assume that the 100 rats can be considered an SRS from the population of all rats born to mothers exposed to high levels of tobacco smoke during pregnancy (note that this assumption may or may not be reasonable, but researchers often assume lab rats are representative of large populations since they are often bred to have uniform characteristics). Let p be the proportion of rats in this population that would go right when running the maze for the first time. A 90% confidence interval for p is
A. 0.8 ± 0.040.
B. 0.8 ± 0.066.
C. 0.8 ± 0.078.
|
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,
|
|
Standard error for the proportion
: Let p represent the proportion of registered voters in the state that would vote for the Republican candidate. The standard error for the proportion of those who phoned in who answered "yes" is
|
|
The p-value of a test
: To determine if this is evidence that students perform worse under uncomfortable conditions, The P-value of a test
|
|
Simple random samples from the appropriate populations
: Based on surveys conducted in 1989 and 1999, a researcher compared the proportion of high school age females interested in a career in science in 1989 with the proportion in 1999. He concluded that the proportions were not significantly different ..
|
|
Find the standard error
: The conservative degrees of freedom for the t distribution are and The standard error, conservative degrees of freedom
|