46. Test the hypothesis using the P-value approach. Be sure to verify the requirements of the test. H0 : p = 0.6 versus H1 : p < 0.6 n = 250, x = 124, (alpha) a = 0.01

47. Test the hypothesis using the P-value approach. H0 : = 100 versus H1 : > 100 n = 35, x = 104, s = 12, (alpha) a = 0.05

48. Test the hypothesis using the P-value approach. H0 : = 50 versus H1 : 6= 50 n = 15, x = 48, s = 4, (alpha) a = 0.05, Population-Normal (why do we need this information?)

49. The average score for a water safety instructor (WSI) exam is 75 with a standard deviation of 12. Fifty scores for the WSI exam are randomly selected.

(a)Find the probability that the average of the fty scores is at least 80.

(b)Find the probability that the average of the fty scores is between 72 and 78.

50. Suppose a 90% condence interval for turns out to be (1000,2100). If this interval was based on a sample of size n=25 explain what assumptions are necessary for this interval to be valid. Find the mean of this particular sample?

51. A simple random sample of size n = 36 is obtained from a population with = 64 and s = 18.

(a) Describe the sampling distribution of x.

(b) What is P( x < 62)?

(c) What is P(62 < x < 70)?

52. Determine std p from the given parameters. Assume the size of the population is 25,000, n = 200, p = 0.75.

53. Suppose that the true proportion of registered voters who favor the Republican presidential candidate is 0.45. Find the mean and standard deviation of the sample proportion for a sample of size 65.

54. Suppose that the true proportion of Americans who save at least 10% of their income is 0.15. if p is the sample proportion of Americans surveyed who save at least 10% of their income from the sample of 68, nd the following probabilities.

(a) P( p > 0.25)

(b) P(0.18 < p < 0.25)

55. Find za 2 for 92% condence level. Make sure to show your work.

56. Find the t-value such that 0.025 of the area under the curve is to the right of the tvalue. Assume the degrees of freedom equal 13.

57. Find ta 2 for a = 0.05 and n = 15. Make sure to show all the necessary work.

58. A Gallup poll of 1487 adults showed that 45% of the respondents have Facebook pages.

(a) Find the margin of error E that corresponds to a 95% condence level.

(b) Find the 95% condence interval estimate of the population proportion p.

59. Construct a 90% condence interval for the population mean, . Assume the population has a normal distribution. A sample of 25 randomly selected Nursing majors has a grade point average of 3.10 with a standard deviation of 0.45. Round to the nearest hundredth.

60. Suppose you are the operations manager for American Airlines and you are considering a higher fare level for passengers in aisle seats. You want to estimate the percentage of passengers who now prefers aisle seats. Assume that you want to be 95% condent that the sample percentage is within 3 percent of the true proportion percentage. How many randomly selected air passengers must you survey if nothing is known about the percentage of passengers who prefer a isle seats.

61. Consider a population having a standard deviation of 20. We want to estimate the mean of the population. How large of a sample is needed to construct a 80% condence interval for the mean if the margin of error is equal to 1.5?

62. According to the Centers for Disease Control and Prevention, 20% of children aged 6 to 11 years are overweight. A school nurse thinks that the percentage of 6 to 11 year-olds who are over weight is higher in her school district.

(a) Determine the null and alternative hypotheses

(b) Explain what it would mean to make a type I error.

(c) Explain what it would mean to make a type II error.

(d) Suppose that a sample evidence indicates that the null hypothesis is not rejected. State the conclusion of the test.

63. Explain what "statistical signicance" means.

64. The P-Value serves as a measure of the strength of evidence against H0. Is it true that a small P-value means that the null hypothesis is strongly rejected or the result is highly statistically signicant.

65. In a survey, 38% of the respondents stated that they talk to their pets on the telephone. A veterinarian believed this result to be too high, so he randomly selected 200 pet owners and discovered that 74 of them spoke to their pet on the telephone. Does the veterinarian have a right to be skeptical? Use the a = 0.01 level of signicance.

66. The population of ALL AMERICANS who drink coffee currently has a population mean of 3 cups a day. You suspect that it is now greater than 3 cups a day. You take a random sample of 50 students and ask them how many cups of coffee they drink a day. You get a sample mean of 3.8, and a sample standard deviation of 1.5. Is this evidence that American drink more than 3 cups a day? Use a = 0.01.

(a) Write the Null and Alternative Hypothesis

(b) Find the t-statistics t0.

(c) Find the P-value.

(d) What is your conclusion? Would you reject the null hypothesis? How would you state

67. In 1994, 52% of parents with children in high school felt it was a serious problem that high school students were not being taught enough math and science. A recent survey found that 256 of 800 parents with children in high school felt it was a serious problem that high school students were not being taught enough math and science. Do parents feel differently today than they did in 1994? Use a = 0.05 level of signicance.

68. "Did you get 8 hours of sleep last night?" is a common question. In a recent survey of 151 post partum women, the folks at the National Sleep Foundation found that the mean sleep time was 7.8 hours, with a standard deviation of 1.4 hours. Does the evidence suggest that postpartum women do not get enough sleep? Use a = 0.05 level of signicance. (Hint: H0 : = 8)