Question

1. (2 points). (True False) The median is very sensitive to extreme data points.

2. (2 points). (True False) The t-distribution approaches the standard normal distribution as sample size increases.

What type of data (attribute, discrete numerical, continuous numerical) is each of the following variables:

3. (2 points) _____________________ Your gender

4. (2 points) _____________________ Your height

Which type of data (nominal, ordinal, interval, ratio) is each of the following variables?

5. (2 points) _____________________ Temperature in degrees Fahrenheit

6. (2 points) _____________________ Your weight

7. (3 points). 500 names are selected from a list containing 1,000 people by choosing every other name. Which sampling method is this?

A) Simple random sample.

B) Systematic sample.

C) Stratified sample.

D) Cluster sample.

8. (3 points). Suppose we want to estimate attrition rates among employees in state government, and we know that our target population is 65 percent male and 35 percent female. Our budget only allows a sample size of 100. We randomly sample 65 males and 35 females. This is an example of ________.

A) simple random sampling.

B) stratified random sampling.

C) cluster sampling.

D) judgment sampling.

9. (3 points). Find a confidence interval for μ assuming that the sample is from a normal population with known population standard deviation.

x = 20, σ = 3, n = 100, 95 percent confidence               

A) (19.405, 20.595)

B) (17.412, 20.588)

C) (19.412, 20.588)

D) (19.412, 21.588)

10. (3 points). Find a confidence interval for μ assuming that the sample is from a normal population with unknown population standard deviation.

x = 20, s = 3, n = 100, 95 percent confidence   

A) (18.412, 20.588)

B) (17.412, 20.588)

C) (19.412, 20.588)

D) (19.405, 20.595)

Answer 1

We would be looking at the first 4 questions here:

Q1) The presence of outliers in the data is the main reason that we use median instead of mean as a measure of the central tendency of the data. This is because median is the middle value of the data and therefore is not affected by the outliers presence. Therefore the given statement is False here.

Q2) As the sample size of t distribution increases, and hence the degrees of freedom become larger and larger, the peak of the t distribution decreases and the frequency in the tail decreases. therefore yes they move closer to the standard normal distribution and hence the given statement is True here.

Q3) As there are only 2 possible genders ( or 3 if we take no gender ), there are only 3 categories possible here.Therefore it is a non numerical categorical variable. (It is a discrete non numerical variable )

Q4) Height can have any value between any two heights for example there are infinite heights possible between 5 and 6 ft. like 5.1 ft, 5.11 ft and so on..

Therefore Height is a continuous numerical variable.