Question

1. if someone added the number 20 to the set of numbers {1, 2, 4, 5, 12}, would that increase or decrease the standard deviation of the set?
2. which of these approaches would give the best indication of how a particular town is planning on voting on an issue in an election?

a. interviewing 100 political activists in the town as to their predictions.
b. taking a phone survey of 500 randomly selected likely voters.
c. having 500 pedestrians in the main city park complete a survey.

1. the box plot below summarizes 15 data values.

what is the median of the data set?

Explanation:

18.

Step1: Recall standard - deviation concept

Standard deviation measures the spread of data.

Step2: Analyze the new data point

The original set is {1, 2, 4, 5, 12}. The number 20 is far from the other values. Adding it will increase the spread of the data.

A phone - survey of 500 randomly selected likely voters (Option B) is most representative as political activists (Option A) may have a bias, and pedestrians in a park (Option C) may not be a representative sample of all voters.

Step1: Recall box - plot properties

In a box - plot, the vertical line inside the box represents the median.

Step2: Identify the median value

From the box - plot, the vertical line inside the box is at 7.

Answer:

Increase

19.