# Statistics

1. Which of the following statements are correct?
a. A normal distribution is any distribution that is not unusual.
b. The graph of a normal distribution is bell-shaped.
c. If a population has a normal distribution, the mean and the median are not equal.
d. The graph of a normal distribution is symmetric.

Using the 68-95-99.7 rule:
Assume that a set of test scores is normally distributed with a mean of 100 and a standard deviation of 20. Use the 68-95-99.7 rule to find the following quantities:
Suggest you make a drawing and label first…
a. Percentage of scores less than 100
b. Relative frequency of scores less than 120
c. Percentage of scores less than 140
d. Percentage of scores less than 80
e. Relative frequency of scores less than 60
f. Percentage of scores greater than 120

2. Assume the body temperatures of healthy adults are normally distributed with a mean of 98.20 °F and a standard deviation of 0.62 °F (based on data from the University of Maryland researchers).
a. If you have a body temperature of 99.00 °F, what is your percentile score?
b. Convert 99.00 °F to a standard score (or a z-score).
c. Is a body temperature of 99.00 °F unusual? Why or why not?
d. Fifty adults are randomly selected. What is the likelihood that the mean of their body temperatures is 97.98 °F or lower?
e. A person’s body temperature is found to be 101.00 °F. Is the result unusual? Why or why not? What should you conclude?
f. What body temperature is the 95th percentile?
g. What body temperature is the 5th percentile?
h. Bellevue Hospital in New York City uses 100.6 °F as the lowest temperature considered to indicate a fever. What percentage of normal and healthy adults would be considered to have a fever? Does this percentage suggest that a cutoff of 100.6 °F is appropriate?

1. 1. B and D

http://www.oswego.edu/~srp/stats/6895997.htm

2. a-c, e-h. Z = (score-mean)/SD

Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportions related to the Z scores.

2d. Z = (mean1 - mean2)/standard error (SE) of difference between means

SEdiff = √(SEmean1^2 + SEmean2^2)

SEm = SD/√(n-1)

If only one SD is provided, you can use just that to determine SEdiff.

Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion related to the Z score.

posted by PsyDAG

First Name

## Similar Questions

1. ### Statistics

1. Which of the following statements are correct? a. A normal distribution is any distribution that is not unusual. b. The graph of a normal distribution is bell-shaped. c. If a population has a normal distribution, the mean and
2. ### statistics

Which of the following statements are correct? a. a normal distribution is any distribution that is not unusual b. the graph of a normal distribution is bell-shaped c. if a population has a normal distribution, the mean and the
3. ### Statistics

Which of the following statements are correct? 1.A normal distribution is any distribution that is not unusual. 2.The graph of a normal distribution is bell-shaped. 3.If a population has a normal distribution, the mean and the
4. ### statistics

which of the following statements are correct? a. a normal distribuiton is any distribution that is not unusual. b. the graph of a normal distribution is bell-shaped. c. if a population has a normal distribution, the mean and the
5. ### statistics

Which of the following statements are correct? a. A normal distribution is any distribution that is not unusual. b. The graph of a normal distribution is bell-shaped. c. If a population has normal ditribution, the mean and the
6. ### statistic

1. Which of the following statements are correct? a. A normal distribution is any distribution that is not unusual. b. The graph of a normal distribution is bell-shaped. c. If a population has a normal distribution, the mean and
7. ### statistics

1. Which of the following statements are correct? a. A normal distribution is any distribution that is not unusual. (True/False) b. The graph of a normal distribution is bell-shaped. (True/False) c. If a population has a normal
8. ### stats

(a) The test had six multiple-choice items that were scored as correct or incorrect, so the total score was an integer between 0 and 6. Do you think that these data are Normally distributed? Explain why or why not. The
9. ### stats

(a) The test had six multiple-choice items that were scored as correct or incorrect, so the total score was an integer between 0 and 6. Do you think that these data are Normally distributed? Explain why or why not. The
10. ### Statistics

If you have a curve with an asymmetric bimodal distribution, is it considered a normal distribution? Or is it only a normal distribution if there is a single bell-shaped curve?
11. ### stat

Which of the following statements is true about the t-distribution with k degrees of freedom? i. the t-distribution is symmetric ii. the t-distribution with k degrees of freedom has a smaller variance than the t-distribution with

More Similar Questions