Question

1. A researcher believes that men have been getting taller in the last 75 years. He knows that 75 years ago the mean height of men was 62 inches with a standard deviation of 18 inches. The researcher randomly selects 80 men and measures their heights. He find that their mean height is 69 inches with a standard deviation of 16. What would the appropriate test be to test if men are getting higher and what is the obtained value?

		single-sample t test;  = 3.91
		single-sample t test;  = 3.48
		Z test;  = 3.91
		Z test;  = 3.48

3 points   

QUESTION 13

According to a recent survey, a typical teenager has 38 contacts stored in his/her cellphone. You take a sample of 20 students at your school and find that the mean number of contacts they have on their phone is 27 with a standard deviation of 5.   What is the appropriate test to use if you want to test your hypothesis using an alpha level of .01?

		Sign Test
		Z-Test
		Single-Sample t Test
		Paired Sample T Test

You have a large bag filled with many pairs of socks. In the bag are:

10 pairs of green ankle socks

7 pairs of green knee socks

4 pairs of blue ankle socks

11 pairs of blue knee socks

22 pairs of white ankle socks

Report all probabilities to FOUR decimal places.  SHOW ALL OF YOUR WORK!

What is the probability of reaching in three times and pulling out a pair of white socks, a pair of green knee socks, and a pair of ankle socks of any color WITHOUT REPLACEMENT?

I walk into the Psych department and notice that there is a large box of differently colored pens and pencils being given away for free. There are: 8 red pens 4 red pencils 6 blue pens 10 blue pencils 15 black pens Report all probabilities as a decimal rounded to FOUR decimal places.   What is the probability of reaching in twice and first pulling out a black pen and then either a red pen or a blue pencil WITH REPLACEMENT?

The average IQ in America is 100. A researcher wants to test the hypothesis that left-handed individuals have different IQs than the average American. He administers an IQ test to 8 left-handed individuals. They have mean 97.4 with a standard deviation of 13.

Test the hypothesis (=.05) that left handed individuals have different IQs than the average Ameican.

BE SURE TO ANSWER ALL PARTS OF THE QUESTION AND SHOW YOUR WORK WHEN YOU CAN.

a) What is the appropriate test?

b) State the null Hypothesis (in words and with means).

c) State the alternative hypothesis (in words and with means).

d) Find the critical value.

e) Calculate the obtained statistic.

f) Report the results. Make a decision.

g) What does your decision mean?

Answer 1