Lasa psychology

M3A2 LASA 1 QUIZ

PSYCHOLOGICAL STATISTICS

>Part I: Computation and Short Answer (80 points)

Question 1.1.

Identify each of the following as examples of nominal, ordinal, interval, or ratio scales of measurement. (4 points each)

1. A poll of registered voters in Florida asking which candidate they support

2. The length of time required for a wound to heal when using a new medicine

3. The number of telephone calls arriving at a switchboard per five-minute period

4. The distance first-year college football players can kick a ball

5. Mental health diagnoses present in an elderly population

6. The rankings of employees on their job performance

Question 2.2.

Two hundred raffle tickets are sold. Your friend has five people in her family who each bought two raffle tickets. What is the probability that someone from her family will win the raffle?

Question 3.3. Jolie has a time of 45 minutes for doing her statistics homework. If the mean is 38 minutes and the standard deviation is 3, calculate Jolie's z score. Once calculated, interpret your findings in terms of Jolie's performance. (HINT: use the normal distribution and the probability that other students performed better or worse.) (Points : 8)

Question 4.4. A psychologist measures units of change for a memory test after students are given an opportunity to sleep only four hours. The following change units were obtained: 7, -12, 4, -7, 3, -10.

Find the a) mean, b) median, c) mode, d) standard deviation, e) range, and f) variance.

Question 5.5. A student scored 81 on a chemistry test and 75 on a history test. For the chemistry test, the mean was 70 and the standard deviation was 20. For the history test, the mean was 65 and the standard deviation was 8. Did the student do better on the chemistry test or the history test? Explain your answer.

Question 6.6. Suppose you want to figure out what to do with your degree in psychology. You ask some fellow students from your psychology program who recently graduated to find out what they are doing with their degree and how much it pays. What type of sampling is this? What are the limitations of this sampling approach?

Question 7.7. Variables in which the values are categories are known as

       Interval variables Nominal variables Ordinal variables Ratio variables

Question 8.8. Before the researcher can conduct a statistical test, the research question must be translated into

       A testable hypothesis Additional observations Mathematical symbols Numbers

Question 9.9. The hypothesis stating that there are no differences, effects, or relationships is

       The alternative hypothesis The baseline hypothesis The null hypothesis The reasonable hypothesis

Question 10.10. A group of students made the following scores on a 10-item quiz in psychological statistics: {5, 6, 7, 7, 7, 8, 8, 9, 9, 10, 10} What is the mean score? (Points : 4)

       6.6 7.2 7.8 8.7

Question 11.11. A group of students made the following scores on a 10-item quiz in psychological statistics: {5, 6, 7, 7, 7, 8, 8, 9, 9, 10, 10} What is the median score?

       6 7 8 9

Question 12.12. A group of students made the following scores on a 10-item quiz in psychological statistics: {5, 6, 7, 7, 7, 8, 8, 9, 9, 10, 10} What is the mode?

       5 7 8 9

Question 13.13. A group of students made the following scores on a 10-item quiz in psychological statistics: {5, 6, 7, 7, 7, 8, 8, 9, 9, 10, 10} What is the range of scores?

       5 6 7 11

Question 14.14. A group of students made the following scores on a 10-item quiz in psychological statistics: {5, 6, 7, 7, 7, 8, 8, 9, 9, 10, 10} What is the variance, treating these scores as a sample?

       1.53

       1.60 2.33 2.56

Question 15.15. The standard normal distribution has all the following properties EXCEPT: (Points : 4)

       The mean, mode, and median are all equal The total area under the curve equals 1 The curve is specified by two parameters, the mean and the standard deviation The curve extends to + and – 3 standard deviations from the mean

Question 16.16. According to the Empirical Rule, approximately _______% of the data in a normal distribution will fall within ±1 standard deviation of the mean.

       34

       68 95 99.7

Question 17.17. In statistical computations, the number of values that are free to vary is known as

       Degrees of freedom Freedom factor Variability index Variation quotient

Question 18.18. Which of the following reflects a Type I error?

       Rejecting the null hypothesis when in reality the null hypothesis is true Rejecting the null hypothesis when in reality the null hypothesis is false Accepting the null hypothesis when in reality the null hypothesis is true Accepting the null hypothesis when in reality the null hypothesis is false

Question 19.19. Which type of sampling is used when the experimenter asks 5 area doctors to refer pregnant women to his study and accepts all women who offer to be in his study? ()

       purposive sampling convenience sampling cluster sampling stratified sampling

Question 20.20. In our statistics equations, n refers to:

       mean standard deviation normal distribution number of subjects

Question 21.21. Which of the following is true regarding alpha?

       it is also known as the level of significance

       value is set by the researcher value is equal to the probability of a type I error all of the above are true

Question 22.22. Macy proposes that boys who play sports are viewed as more attractive than boys who do not play sports. What is her null hypothesis?

       Boys who play sports are not viewed as more attractive than boys who do not play sports Playing sports will influence how attractively boys are viewed Boys who play sports are more attractive than girls who play sports There can be no null hypothesis

Question 23.23. You calculate a t of 2.38 and note that the tabled value for .01 is 3.22 and for .05 is 2.19. You would conclude that the null hypothesis can be:

       Accepted at the .05 level Rejected at the .01 level Rejected at the .05 level None of the above

Question 24.24. A researcher is studying political conservatism among 11 engineering students and 11 humanities students. The number of degrees of freedom for a t test is: (

       22 20 11 10

Question 25.25. A t test for dependent groups should be used instead of a t test for independent samples: (

       If each participant is measured twice Whenever there are equal numbers of subjects in each group Whenever there are only two groups All of the above

Question 26.26. In a normal distribution, what percent of the population falls between -1 and 1 standard deviations of the mean?

       34% 68% 95% cannot tell from the information given

Question 27.27. Which of the following is more affected by extreme scores?

       Mode Mean Median None of the above are affected

Question 28.28. On a histogram, what does the vertical (y) axis refer to?

       Individual scores Frequencies Means Deviation scores

Question 29.29. Which statistic refers to the average amount by which the scores in the sample deviate from the mean?

       Range Standard deviation Median Mode

Question 30.30. Assume a normal distribution for N = 300. How many cases would one expect to find between +1 and -1 standard deviations around the mean?

       102 285 150 204

Question 31.31. A z score of zero tells us that the score is at the________of the distribution.

       Mean Very top Very bottom None of the above since z cannot be zero

Question 32.32. In a unit normal curve, what goes on the x axis?

       Frequencies Observed scores z scores Area

Question 33.33. Which of the following is a measure of variability?)

       Mean Range Interval All of the above

Question 34.34. The only measure of central tendency that can be found for nominal data is the

       Mean Median Mode Midrange

Question 35.35. If the probability of event A is 0.45 and the probability of event B is 0.35 and the probability of A and B occurring together is 0.25, then the probability of A OR B is:

       0.8 1.8 0.1575 0.55

Question 36.36. A researcher knows that the average distance commuting students live from campus was previously 8.2 miles. Because of the rising prices of gasoline, the research wants to test the claim that commuting students now live closer to campus.

What is the correct alternative hypothesis?

       The new mean distance is 8.2 miles. The new mean distance is less than or equal to 8.2 miles. The new mean distance is less than 8.2 miles. The new mean distance is greater than or equal to 8.2 miles.