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PsyB07 - 2006

Quiz 3

Name: Answer Key

ID:

1. (1)Which of these is NOT a part of the central limit theorem

a)

b)

c)

d)

2. (1)Consider the following situation. I have a set of 8 scores. I know that X = 50, and that X1=4 and X6=2. How many degrees of freedom are there remaining in this set of scores?

5

3. (1)We use the t statistic instead of z when:

a)We know the population variance

b)We don't know the population variance

c)When we only have one variable

d)Because Marty said so

4. (1)In terms of the formula I’ve been talking about, the E is analogous to:

a)Values from the distribution that can occur by chance

b)Values from the distribution that we’d expect to obtain

c)The denominator in the independent samples t-test

d)All of the above

e)None of the above

5. (1)Variance Sum Law states that:

a)the variance of the product of two variables is equal to the sum or the difference of the individual variances of the two variables

b)the variance of the sum or difference of two variables is equal to the difference of the individual variances of the two variables

c)the variance of the sum or difference of two variables is equal to the sum of the individual variances of the two variables

d)the variance of the sum or difference of two variables is equal to the product of the individual variances of the two variables

TURN OVER !!!
6. (5)A pharmaceutical company developed a new drug for treating tapeworms in sheep. Clinical trials in which half of the animals were treated with the drug and half were not produced the following data (number of tapeworms found in sheep stomachs). Analyze the data.

Non-Treated / Treated / Difference Scores
40 / 18 / 22
54 / 43 / 11
26 / 28 / -2
63 / 50 / 13
21 / 16 / 5
37 / 32 / 5
39 / 13 / 26
Mean = 40.00 / Mean = 28.57 / Mean = 11.43
Std. Dev. = 14.67 / Std. Dev. = 14.09 / Std. Dev. = 9.91

H0: There is no difference between treated and untreated sheep

H1:There is a significant difference between treated and untreated sheep

Formula:

Final answer:1.49

Decision (reject or fail to reject H0): Fail to reject null

Conclusion: There is no difference between treated and untreated sheep

t-tablez-table

df / Critical t (two-tailed, alpha=.05) / z / Smaller Portion
1 / 12.706 / 1.1 / 0.1357
2 / 4.303 / 1.2 / 0.1151
3 / 3.182 / 1.3 / 0.0968
4 / 2.776 / 1.4 / 0.0808
5 / 2.571 / 1.5 / 0.0668
6 / 2.447 / 1.6 / 0.0548
7 / 2.365 / 1.7 / 0.0446
8 / 2.306 / 1.8 / 0.0359
9 / 2.262 / 1.9 / 0.0287
10 / 2.228 / 2.0 / 0.0228
11 / 2.201 / 2.5 / 0.0062
12 / 2.179 / 3.0 / 0.0013
13 / 2.160 / 3.5 / 0.0002
14 / 2.145 / 4.0 / 0.0000