Q#1

 

Beck Depression Inventory (BDI) was originally invented and validated in the United States but proved to be a highly reliable diagnostic tool for identifying severity of depression in other countries too. Based on BDI-based national assessment screening for depression, Finland has national BDI average of 2.59 (std = 1.17) and Denmark has national BDI average of 5.0 (std = .4). Imagine that you are a clinician working with people Denmark and Finland and try to answer questions below.

1. Your patient has a BDI score of 4. You should you be concerned about this patient if Answerabc

a. she is from Denmark

b. she is from Finland

c. there is no reason to believe that the country matters

2. Your patient has a BDI score of 5.5. Should you be more concerned about this patient if Answerabc

a. she is from Denmark

b. she is from Finland

c. there is no reason to believe that the country matters

3. A BDI score of 3 will indicate severe levels of depression (a great deal above population average) in Answerabcd

a. Finland

b. Denmark

c. both countries

d. neither country

4. Convert a BDI score of 3.5 from Finland and a BDI score of 3.5 from Denmark to z-scores.  Answerabcd

a. z-score (Denmark) = -3.75 and z-score (Finland) = .78

b. z-score (Finland) = -3.75 and z-score (Denmark) = .78

c. conversion to z-scores is not possible.

d. conversion to z-scores is unnecessary as we know everything we need to know from raw BDI scores already.

5. Convert a z-score to percentile for a patient from Finland and show where this patient is in relation to the population of Finland. Answerabcd

a. appr. 78 percentile (22% of the population are MORE depressed than this person)

b. 40 percentile (60 % of the population are MORE depressed than this person)

c. appr. 29 percentile (71% of the population are LESS depressed than this person)

b. 70 percentile (30 % of the population are LESS depressed than this person)

6. Convert a z-score to percentile for a patient from Denmark and show where this patient is in relation to the population of Denmark.  Answerabcd

a. 23 percentile (77% of the population are LESS depressed than this person)

b. 50 percentile (50 % of the population are MORE depressed than this person)

c. below .1 percentile (99.9% of the population are MORE depressed than this person)

b. 70 percentile (30 % of the population are LESS depressed than this person)

Q#2

The univariate statistics were obtained with SPSS for the following three variables: age of participants, gender of participants (male vs. female), and race of participants (White, African American, Hispanic). The results are presented in the table below.

Mean

St. Deviation

N

Age

25.5

3.1

200

Gender

1.4

.24

200

Race

2.56

1.23

200

Using the information in the table, answer the questions below:

1. Interpret the mean for Age (25.5): AnswerABCD

(A) 50% of all participants were 25.
(B) 25.5 is the average age of all participants in this sample.
(C) 50 % of all participants were 28 (25 + 1 std).
(D) The mean for Age cannot be interpreted as it represents nothing that exists physically.

2. Interpret the mean for Gender (1.4): AnswerABCD

(A) 40% of all participants in the sample were women.
(B) 60% of all participants in the sample were men.
(C) Both A and B are correct.
(D) The mean for Gender cannot be interpreted as it represents nothing that exists physically.

3. Interpret the mean for Race (2.56): AnswerABCD

(A) 56% of all participants in the sample were White.
(B) 34% of all participants in the sample were African American.
(C) 50% of all participants in the sample were Hispanic.
(D) The mean for Race cannot be interpreted as it represents nothing that exists physically.

Q#3

 

Apple conducted a test of customer ratings for their new i-Phone. Customers of various demographics were given new i-Phone models to try and then asked to rate them and give reviews. Ratings were on a 6-point Likert scale: Totally hated (1), Did not like it (2), Neutral (3), OK (4), Like a lot (5), Best of the best (6). Below are the ratings and the univariate statistics on the ratings.

Mean = 3.2, Median = 3, std = .96, N (sample size) = 1550.

i-Phone Liking Scores()Totally hated (1)10Did not like it (2)160Neutral (3)640OK (4)500Like a lot (5)210Best of the best (6)20

Using these data, answer several questions below.

1. If we want to know how many respondents had a negative attitude towards a new phone, we would compute: Answerabcd

a. Frequency for those who indicated that they hated the phone.

b. Frequency for those who indicated that they did not like the phone

c. Frequency for those who were neutral

d. Cumulative frequency for those whose answers were did not like and totally hated

2. Estimate skewness in this data set by comparing the mean and the median ratings. Based on your analysis, do you expect Answerabc

a. Slight positive skewness

b. Slight negative skewness

c. No skewness

3. Based on your analysis of skewness, what measure of central tendency should be used in this case? Answerabc

a. Only the mean

b. Only the median

c. Both the mean and the median will be equally informative

4. Finish the sentence. Combining information from the mean and the standard deviation, we expect 68% of the participants to be in the range of  Answerab

a. 1.28 5.12

b. 2.24 4.16

5. True or false? Within 96% of the participants (+/- 2 standard deviations around the mean), there were no responses of the totally hated kind. Answerab

a. True

b. False    

6. What are your conclusions about the new phone? Answerabcd

a. The most typical response to the phone is “neutral”.

b. We do not need to worry about totally hated responses because those are outliers (too extreme to consider representative for this group).

c. The phone did ok on the tests of customer satisfaction and can be recommended for serial production.

d. All of the above are valid conclusions.