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ECON 2500: Introductory Statistics for Economists Midterm Exam -Solutions

I. (60 points) Multiple choice questions (no explanation needed)

1. Using the standard normal distribution tables, what is the size of the area under the standard normal curve corresponding to –0.3 < Z < 1.2?
A) 0.3821 B) 0.8849 C) 0.5028 D) 0.2815 Answer: C

2. A high school guidance counselor wants to study the later earnings of the class of 2000. The high school had 800 graduates in the class of 2000; among them, 400 obtained college degrees and the other 400 did not. In the year 2010, the counselor randomly selects 20 individuals from among those who obtained college degrees, and another 20 individuals among those who didn’t obtain college degrees. Earnings data is collected on these 40 selected individuals. This study is:

A) A designed experiment, in which the “treatment group” receives a college degree, and

the “control group” gets no college degree.

B) Based on “anecdotal evidence”, and hence is not reliable.

C) An observational study. However, the 40 selected individuals are not a Simple Random

Sample.

D) An observational study, in which the 40 selected individuals are a Simple Random

Sample.

C

3. Following the previous question. From the data collected, the high school guidance

counselor finds that the average earnings of the 20 individuals who didn’t obtain college

degrees is \$23,000. The value \$23,000 is

A) a population parameter.

B) a sample parameter.

C) a statistic for the population.

D) a statistic for the sample