1) Trails in an experiment with a polygraph include 96 results that include 22 case of wrong results and 74 correct results. Use a 0.01 significance level to test the claim that such polygraph results are correct less than 80% of the time. Identify the null hypothesis, test statistic, p-value, conclusion about the null hypothesis, and final conclusion that address the original claim. Use the P-method.
Use the normal distribution as an approximation of the binomial distribution. What are the null and alternative hypotheses? The test statistic is z= The P- value is?
2) In a test of effectiveness of garlic for lowering cholesterol, 44 subjects were treated with garlic in a processed tablet form. Cholesterol levels were measured before and after the treatment. The changes in their levels of LDL cholesterol (in mg/dL) have a mean of 4.3 and a standard deviation of 18.6. Complete parts (a) and (b) below.
A. What is the best point estimate of the population mean net change in LDL cholesterol after the garlic treatment? The best point estimate is ___ mg/dL. (Type an integer or a decimal.)
B. Construct a 90% confidence interval estimate of the mean net change in LDL cholesterol after the garlic treatment. What does the confidence interval suggest about the effectiveness of garlic in reducing LDL cholesterol?
What is the confidence interval estimate of the population mean u (mew)? __ mg/dL< u <____ mg/dL (Round to two decimal places as needed.) What does the confidence interval suggest about the effectiveness of the treatment?
3) A simple random sample of 55 screws supplied by a certain manufacturer is obtained, and the length of each screw in measured. The sample mean is found to be 0.617 in. Assume that the standard deviation of all such length is 0.017 in, and use a 0.05 significance level to test the claim that the screws have a mean length equal to 5/8 in. (or 0.625in), as indicated on the package labels.
Do the screw lengths appear to be consistent with the package label? What are the null and alternative hypotheses? What us the value of the test statistic? The P-value is?
4) Claim: The mean IQ score of the statistics professors is greater than115. Sample Data: n=20, x=117, s=11. The significance level is 0.05 A) What is the test Statistic? = ____ Round to 3 decimal places B) What is the critical
Values= ___ (use the t distribution table) Round to 3 decimal places as needed, Use a comma to separate answers as needed C) What is the P-Value = ___ Round to four decimal places as needed D) What is the final Conclusion:
5) Assume that a simple random sample has been selected from a normally distributed population and test the given claim. Identify the null and alternative hypotheses, test statistic, P-value, critical value(s), and state the final conclusion that addresses the original claim. A simple random sample of pages from a dictionary is obtained.
Listed below are the numbers of word defined on those pages. Given that this dictionary has 1459 pages with defined words, the claim that there are more than 70,000 defined words is the same as the claim that the mean number of defined words on a page is greater than 48.0. Use a 0.05 significance level to test this claim.
What does the result suggest about the claim that there are more than 70,000 defined words in the dictionary? 66 38 73 53 52 71 42 39 61 95 what are the null and alternative hypotheses? Identify the test statistic.
Identify the P-value Identify the critical value(s). State the final conclusion that addresses the original claim. Do the results suggest that there are more than 70,000 defined words in the dictionary?
6) Use the given information to find the minimum sample size requires to estimate an unknown population mean μ. How many adults must be randomly selected to estimate the mean FICO (credit rating) score of working adults in a country?
We want 90% confidence that the sample mean is within 5 points of the population mean, and the population standard deviation is 70. The minimum sample size is _________adults.
7) Test of older baseballs showed that when dropped 21 ft. onto a concrete surface, they bounced an average of 238.1 cm. In a test of 40 new baseballs, the bounce height had a mean of 239.3 cm. Assume that the standard deviation of bounce heights of all new baseballs is 4.6 cm. Use a 0.05 significance level to test the claim that the new baseballs have bounce heights with a mean different from 238.1 cm. Are the new baseballs different?
What are the null and alternative hypotheses?