Reference no: EM132848507

1. Researchers want to determine the longevity of domestic automobiles produced and sold by car dealerships in 2000. The following are different sampling techniques that the researcher could use.

Techniques:

1) The researchers randomly selected 5 dealerships in the U.S. and found the lifetimes of all the cars from 2000 in each.

2) The researchers listed all of the cars from the 5 dealerships and found the lifetime of every 25th car on the list.

3) The researchers divided the cars based on engine type, and then found the lifetimes of all for each engine type.

4) The researchers listed all of the cars. They then found the lifetimes of randomly selected cars.

5) The researchers went to one dealership on a given day and measured the lifetimes of the cars there.

Classify each according to the following Sampling Methods:

a) Simple random sampling

b) Stratified sampling

c) Systematic sampling

d) Cluster sampling

e) Convenience sampling

Each has a unique sampling method.

2. A random sample of 40 bus riders was surveyed on a particular stop of a route on a Monday between 2:00 and 3:00 pm. The frequency distribution below shows the distribution of wait times for a bus (in minutes). Show all work for the following questions.

Wait Time (minutes) Frequency Cumulative Relative

Frequency

1.0 - 2.9 3

3.0 - 4.9 16

5.0 - 6.9 0.725

7.0 - 8.9 0.925

9.0 - 10.9 3

Total 40

a) Complete the frequency table with frequency and cumulative relative frequency. Express the cumulative relative frequency to three decimal places.

b) What percentage of the wait times was less than 5 minutes?

c) Which of the following wait time groups does the median of this distribution belong to?

1.0 - 2.9, 3.0 - 4.9, 5.0 - 6.9, 7.0 - 8.9, or 9.0 - 10.9? Explain.