Statistics and Probability Answers

The average per capita spending on health care in United States is $5274. If the standard

deviation is $600 and the distribution of health care spending is approximately normal, what is the probability that a randomly selected person spends more than $6000? Find the limits of the middle 50% of individual health care expenditures.

a company produces mosquito repellents that have a period of effectiveness that is approximately normally distributed with a mean of 300 hours and a standard deviation of 30 hours. A sample of 40 repellents was taken and the average period of effectiveness is computed as 290 hours. Test the hypothesis that µ = 300 against the alternative that µ ≠ 300

Four cards are drawn from a desk without replacement. Find these probabilities.

a. All cards are jacks.

b. All cards are black cards.

c. All cards are hearts.

A medical trial is conducted to test whether or not a new medicine reduces cholesterol by 25% test at 99% confidence level

How does the t-distribution differ from a normal distribution? A. The t-distribution has a mean of 0. B. The t-distribution has a thicker tail. C. The t-distribution is symmetric in the middle. D. The t-distribution is bell-shaped.

A survey of 300 Senior High School learners shows that they read on average of 20 hours per week with a margin of error of 2.2 hours at 95% level of confidence.

21. What is the sample mean? A. 20 B. 300 C. 2.2 D. 0.05

22. Which of the following is the upper limit of the interval? A. 15 B. 17.8 C. 22.2 D. 1.96

23. What is the lower limit of the confidence interval? A. 17.8 B. 1.96 C. 22.2 D. 4.4

24. What is the length of the confidence interval? A. 17.8 B. 22.2 C. 4.4 D. 2.

If the variance of the population is 5, what is the variance of the sampling distribution of the means of size 3 drawn from this population?

A sample of 160 people has a mean age of 27 with a population standard deviation of 5. Test the hypothesis that the population mean is 26.7 at =0.05

the average cholesterol of a certain canned goods is 180 milligrams, and the standard deviation is 12 milligrams. assume that the variable is normally distributed. if a sample of 16 canned goods is selected, what is the probability that the mean of the sample will be greater than 172 milligrams

the average number of pages in a novel is 276 witha standard deviation of 18 pages. is a sample of 40 novels is randomly chosen, what is the probability that the average number of pages in these books is between 268 and 281?