Statistics for T-Tests

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1. T-tests compare -- averages.
  a. 2
  b. 3
  c. 4
  d. 5
2. T-ests give the probability that the differences are caused by
  a. design
  b. chance
  c. circumstances
  d. the data
3. If is usually said that if the probability is less than --, than the differences is "significant".
  a. 0.55
  b. 0.5
  c. 0.01
  d. 0.05
4. Group A scores are 10, 10, 12, 15, 16 and group B scores are 9,9,14,16,17. You do the unpaired t-test. t=
  a. 0.0235
  b. 0.1894
  c. 0.8523
  d. 1.8892
5. Data as in q4. Degrees of freedom =
  a. 2
  b. 4
  c. 6
  d. 8
6. Data as in q4. The standard error of diviation is =
  a. 2.112
  b. 3.668
  c. 3.889
  d. 6.222
7. Data as in q4. The two means are=
  a. 12.60
  b. 14.98
  c. 13.01
  d. a and c
  e. a and b
8. Data as in q4. The standards of deviation -
  a. 3.66 and 5.66
  b. 2.79 and 3.81
  c. 3.11 and 4.67
  d. 1.22 and 2.56
9. Data in q4 and two-tailed P vale of .08545 makes it --- statistical significant.
  a. very
  b. a little
  c. not
  d. sometimes
10. You use a paired test when the scores are =
  a. matched
  b. unmatched
  c. random
  d. even
11. Data as in q4 for the paied test. t =
  a. 0.5623
  b. 0.6667
  c. 1.5654
  d. 2.4532
12. Paired test as with data of q4. df=
  a. 2
  b. 4
  c. 6
  d. 8
13. The paired t-test of q4 data is statistically
  a. significant
  b. insignificant
  c. correct
  d. meaningful
14. The t-test is the same as
  a. correlation
  b. regression
  c. ABOVA
  d. nothing above
15. The t-value will be positive if the first mean is larger than the second and negative if it is smaller. Once you compute the t-value you have to look it up in a table of significance to test whether the ratio is large enough to say that the difference between the groups is not likely to have been a chance finding. To test the significance, you need to set a risk level (called the alpha level). In most social research, the "rule of thumb" is to set the alpha level at ___.

  a. 0.2
  b. 0.3
  c. 0.4
  d. 0.5
16. In the t-test, the degrees of freedom is the sum of the persons in both groups minus __.
  a. 1
  b. 2
  c. 3
  d. 4
17. The t test employs the statistic (t) to test a given statistical hypothesis about the ___ of a population (or about the means of two populations).
  a. standard deviation
  b. mean
  c. degrees of freedom
  d. data
18. The Standard ____, or Standard ____ of the Mean, is an estimate of the standard deviation of the sampling distribution of means, based on the data from one or more random samples. Numerically, it is equal to the square root of the quantity obtained when s squared is divided by the size of the sample.
  a. data
  b. deviation
  c. score
  d. error
19. A statistical test of hypothesis is referred to as a "____-sample t-test." For example, a researcher might be interested in determining whether the average family income among Chicago residents was higher or lower that the average family income in the entire United States.
  a. one
  b. two
  c. three
  d. four
20. In practice, the two-sample t-test is a more commonly used statistic. This statistic can evaluate whether or not there are significant differences in the means of ___ independently sampled populations.

  a. one
  b. two
  c. three
  d. four
21. A ___ sample binomial test allows us to test whether the proportion of successes on a two-level categorical dependent variable significantly differs from a hypothesized value.

  a. one
  b. two
  c. three
  d. four
22. T-test concerns a number of procedures concerned with comparing two averages. It can be used to compare the difference in weight between two groups on a different diet, or to compare the proportion of patients suffering from complications after two different types of operations, or the number of traffic accidents on two busy junctions.
  a. true
  b. false
  c. sometimes true
  d. sometimes false
23. The formula for the t-test is a ___. The top part of the ratio is just the difference between the two means or averages. The bottom part is a measure of the variability or dispersion of the scores.
  a. number
  b. ratio
  c. proportion
  d. all of the above
24. The paired t test compares ___ paired groups. It calculates the difference between each set of pairs, and analyzes that list of differences based on the assumption that the differences in the entire population follow a Gaussian distribution.

  a. 1
  b. 2
  c. 3
  d. 4
25. Group A is 8,5, 7,2,4,5 Group B is 9,6,5,3,3,6 The Paired t-test is
  a. 0.4434
  b. 0.4152
  c. 0.5443
  d. 0.6445
26. Data from Q25. df=
  a. 2
  b. 3
  c. 4
  d. 5
27. Data from Q25. The M of group A is
  a. 5.0
  b. 5.17
  c. 5.33
  d. 5.89
28. The ___ value answers this question: If the treatment really had no effect, what is the chance that random sampling would result in an average effect as far from zero (or more so) as observed in this experiment?

  a. A
  b. M
  c. P
  d. X
29. Use the t test only to compare two groups. To compare ___ or more matched groups, use repeated measures one-way ANOVA followed by post tests. It is not appropriate to perform several t tests, comparing two groups at a time.

  a. 1
  b. 2
  c. 3
  d. 4
30. You can be ___% sure that this interval contains the true treatment effect. When the P value is larger than 0.05, the 95% confidence interval will start with a negative number (representing a decrease) and go up to a positive number (representing an increase).

  a. 80
  b. 85
  c. 90
  d. 95
31. If the t ratio is large (or is a large negative number), the P value will be ____. The number of degrees of freedom equals the number of pairs minus 1.
  a. large
  b. unclear
  c. disputed
  d. small
32. Data fror Q25. The two-tailed P value equals 0.6952 By conventional criteria, this difference is considered to be ____ statistically significant.

  a. some
  b. always
  c. not
  d. often
33. In general, the ___ hypothesis is the logical antithesis of whatever hypothesis it is that the investigator is seeking to examine.
  a. real
  b. opposite
  c. null
  d. calculated
34. For experiments testing differences between means, the null hypothesis is that the difference between means is some specified value. Usually the null hypothesis is that the difference is ___.

  a. 0
  b. 1
  c. 2
  d. 3
35. The null hypothesis is often the reverse of what the experimenter actually believes; it is put forward to allow the data to ____ it.
  a. explain
  b. agree with
  c. proof
  d. contradict
36. The t-Test: We use this statistical test to compare our sample populations and determine if there is a significant difference between their means. The result of the t-test is a ‘t’ value; this value is then used to determine the ___ value

  a. a
  b. d
  c. f
  d. p
37. There are two types of t-tests, the ___ and paired t-test.

  a. unpaired
  b. simple
  c. standard
  d. mean
38. In this ___ t-test your samples are related. You collected data before and after some manipulation of your subjects. Ex.: Pulse before and after 3 cups of coffee.

  a. unpaired
  b. paired
  c. related
  d. group
39. This type of t-test is used when you have independent samples. In other words your samples are not directly related to one another. Ex.: Index finger length between males and females.

  a. unpaired
  b. paired
  c. group
  d. sample
40. Te Cochran variant of the t-test is used when the standard deviations of the independent sets ____ significantly;
  a. differ
  b. do not differ
  c. both
  d. neither