Statistics and Probability Answers

One sample has a mean of M= 6 and a seond sample has a mean of M= 12. The two samples are combined into a single set of scores.&
A) what is the mean for the combined set if both of the original samples have n = 5 scores?&
B) what is the mean for the combined set if the first sample has n = 4 score and the second sample has n = 8? &

Calculate SS variance and standard deviation for the following sample of n = 5 scores&
10, 3, 8, 0, 4 &

Suppose 12 out of 30 families on your street have a cat or a dog as a pet.
a. what is the experimental probability that a randomly selected family in your neighborhood will have a cat or a dog as a pet?
b. based on P(cat or dog) from part (a), predict how many cat- or dog-owning families you can expect amoung 57 families in your neighborhood.

Describe a situation where you would need each of the following tests: Multiple Regression, t-test for Related Samples, Correlational Analysis, and the z-test. Give one example for each test.

An LU professor is interested in whether there is a difference between undergraduate students and graduate students in the amount of time spent praying each day. The professor gathers information from random samples of undergraduate and graduate students on the LU campus. The amount of time praying is normally distributed and is measured on an interval/ratio scale.
& & & & Graduate Undergraduate
& & & & 15 & & & & & & & & & & 9
& & & & 17 & & & & & & & & & 11
& & & & 10 & & & & & & & & & & 9
& & & & 13 & & & & & & & & & & 6
& & & & 11 & & & & & & & & & & 5
& & & & 17 & & & & & & & & & & 6
a. What statistical test should be used to analyze the data?

A researcher hypothesizes that people who listen to music via headphones have greater hearing loss and will thus score lower on a hearing test than those in the general population. On a standard hearing test, the overall mean for the general population is 22.5. The researcher gives this same test to a random sample of 12 individuals who regularly use headphones. Their scores on the test are 15, 14, 20, 20, 25, 22, 21, 19, 16, 17, 21, 22.

a. What statistical test should be used to analyze the data?

A researcher hypothesized that the pulse rates of long-distance athletes differ from those of other athletes. He believed that the runners’ pulses would be slower. He obtained a random sample of 10 long-distance runners. He measured their resting pulses. Their pulses were 45, 45, 64, 50, 58, 49, 47, 55, 50, 52 beats per minute. The average resting pulse of athletes in the general population is normally distributed with a pulse rate of 60 beats per minute.

a. What statistical test should be used to analyze the data?

b. Is this a one- or two- tailed test?

c. What are H0 and Ha for this study?

d. Find tcv from appendix A in Jackson’s text.

e. Compute t obt

f. Should H0 be rejected? What should the researcher conclude?

A researcher is interested in whether students who attend private high schools have higher average SAT Scores than students in the general population. A random sample of 90 students at a private high school is tested and and a mean SAT score of 1030 is obtained. The average score for public high school student is 1000 (σ= 200).

a. Is this a one- or two tailed test?

b. What are H0 and Ha for this study?

c. Compute Z obt

d. What is the Z critical value (Z cv ) using a 0.05 alpha level?

e. Should H0 be rejected? What should the researcher conclude?

f. Determine the 95 % confidence interval for the population mean, based on the sample mean.

Do you have a website that i can scan my homework and send it to, you guys work the problems and send back the answers ? not sure how this works. Thanks

Convert each of the following z intervals to raw score x intervals.
D.) z< -1
E.) 1 < z< 2
f.) z > 1.5