Question

In: Statistics and Probability

1. Students were provided a one-time survey with questions about course load and sleep habits: -...

1. Students were provided a one-time survey with questions about course load and sleep habits:

- Are you taking another course at the same time as biostats?

- On a normal night during the summer, how much do you sleep?

question: Are sleep times of college students different depending on their course load?

a. Cross-sectional and observational

b. Cross-sectional and experimental

c.Longitudinal (retrospective) and experimental

d.Longitudinal (prospective) and experimental

e.Longitudinal (prospective) and observational

f.Longitudinal (retrospective) and observational

2. An investigator compares average BMI from a simple random sample of students in a school with vending machines to average BMI from a simple random sample of students in a school in the same district without vending machines.

a. Paired differences b.Independent samples c. none d. Historical controls      

Cardiovascular disease risk factors are compared in couples.

  a. Paired differences b. Independent samples c. none d. Historical controls      

A nutritional test is applied to a random sample of individuals. Results are compared to expected (historical) means.

a. Paired differences b. Independent samples c. none d. Historical controls

3. As a measure of center, the mean is paired with which measure of spread?

A. Standard deviation

B. Median

C. Range

D. Interquartile range

4. A _________ is a numerical summary that describes a sample.

A. population

B. sample

C. statistic

D. parameter

5. How are the variance and the standard deviation related?

A. The standard deviation is the variance squared.

B. They are the same.

C. The standard deviation is the square root of the variance.

D. They are not related.

Solutions

Expert Solution

1. Option: a. Cross-sectional and observational

(Since students were provided a one-time survey, it is cross-sectional study. Here we observe individuals without manipulation or intervention, so it is observational study).

2.i. An investigator compares average BMI from a simple random sample of students in a school with vending machines to average BMI from a simple random sample of students in a school in the same district without vending machines:

a. Paired differences (we use same student and take two measures: 1. with vending machine and 2: without vending machine).

ii. Cardiovascular disease risk factors are compared in couples: Option:  a. Paired differences

iii. A nutritional test is applied to a random sample of individuals. Results are compared to expected (historical) means: Option: d. Historical controls

3. Option: A. Standard deviation

4. A Option C. statistic is a numerical summary that describes a sample.

5. Option: C. The standard deviation is the square root of the variance.

orchestra answered 1 year ago
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