Misc (a) What happens to the width of the CI when i. n increases ii. Confidence level increases? (b) Are assumptions for Normal approximation for the proportion CI satistied when i. n = 100, P = 0.2 ii. n=300, P=0.01? (c) For a sample of 36 bags of M&M's, a 95% confidence interval for =the average number of M&M's per bag was found as [23.6; 24.8]. Circle all that apply: i. The sample mean was 24.0 ii. we are 95% sure that μ will belong to the above interval iii. for 95% of all M&M's bags the number of candies in a bag will belong to the above interval iv. the population mean m cannot be above 25 v. the C.I. was computed incorrectly because both numbers are fractions

X is a normal variable with mean of 8 and variance of 97. What is the z-score when x = 3?

Premature-birth Risk Found Higher for Teens (reported in the Sacramento Bee, April 27, 1995, p. A7) The youngest girls [in the study], those aged 13 to 17, were 90 percent more likely than the women in their early 20's to deliver prematurely. "The relative risk was 1.9. But what is the absolute risk for women in their 20's which is used as the baseline?

Overproduction of uric acid in the body can be an indication of cell breakdown. This may be an advance indication of illness such as gout, leukemia, or lymphoma. Over a period of months, anadult male patient has taken eight blood tests for uric acid. The mean concentration was ?̅= 5.35mg/dl. The distribution of uric acid in healthy adult males can be assumed to be normal, with σ = 1.85 mg/dl.a. Find a 90% confidence interval for the population mean concentration of uric acid in this patient’s blood. What is the margin of error?b. Find a 99% confidence interval for the population mean concentration of uric acid in this patient’s blood. What is the margin of error? Compare the lengths of the confidence intervals for parts (a) and (b). As the confidence levelsincrease, do the confidence intervals increase in length?

True or false? In a sample with s=8, a score of x=52 corresponds to z= -.50. The mean for this sample is M=48.

The distribution of scores on a standardized test is approximately Normal with standard deviation of σσ = 22. If a sample of 150 students had a mean score of x¯x¯ = 74.3, use this to find a 99% confidence interval for the mean score of all students on this test. We are 99% confident that the the mean score of students on this test was in the interval     What is the margin of error for your confidence interval? Margin of error =

Suppose the distribution of maximum monthly January temperatures in Sydney is normal with mean, μ = 25.95 OC and a standard deviation, σ = 1.13 OC. What is the value of the temperature that cuts off the lower 2.5% of this population?  (1 dp)   What is the value of the temperature that cuts off the upper 25% of this population?   (1 dp)

(d) Estimate the total charge for an individual who stays 11 days in the hospital. (3 decimals)(e) Suppose we compare two patients and one stays 3 days longer in the hospital than the other.What is the expected difference in total charges between these patients?Suppose the sample correlation coefficient is ? = 0.88. Is there evidence of a significantcorrelation between the length of stay and the total charge? Run the appropriate test at ? = 0.05.

The systolic blood pressure (given in millimeters) of males has an approximately normal distribution with mean  ? = 120  and standard deviation  ? = 18. (a) Calculate the z-scores for the male systolic blood pressures 100 and 140 millimeters. (Round your answers to two decimal places.) 100 mm      z  =    140 mm z  =    (b) If a male friend of yours said he thought his systolic blood pressure was 2.5 standard deviations below the mean, but that he believed his blood pressure was between 100 and 140 millimeters, what would you say to him? (Enter your numerical answer to the nearest whole number.) He is  ---Select--- (correct or incorrect) because 2.5 standard deviations below the mean would give him a blood pressure reading of  millimeters, which is  ---Select--- (below, above or in) the range of 100 to 140 millimeters.

"The number of accidents..." please help with i, ii, and iii