A focus group of 10 adults was chosen to evaluate
Question
A focus group of 10 adults was chosen to evaluate the performance of a candidate during a
presidential debate. Each member of the group rated the overall performance on a scale of
1(poor) to 10 (superior). The ratings given the candidate were as follows:4587987367
Calculate the (a) range, (b) variance, and (c) standard deviation for these rating scores.
Solution
The ratings are:
4,5,8,7,9,8,7,3,6,7
Range
Range = Maximum value − Minimum value
=9-3
=6
Variance
The formula for variance (σ2)
N
1
σ2 ¿
N ∑ (xi−μ)( xi−μ)
i=1
N = number of observations = 10
μ = mean of the data
xi = individual observations
Mean
Question
A focus group of 10 adults was chosen to evaluate the performance of a candidate during a
presidential debate. Each member of the group rated the overall performance on a scale of
1(poor) to 10 (superior). The ratings given the candidate were as follows:4587987367
Calculate the (a) range, (b) variance, and (c) standard deviation for these rating scores.
Solution
The ratings are:
4,5,8,7,9,8,7,3,6,7
Range
Range = Maximum value − Minimum value
=9-3
=6
Variance
The formula for variance (σ2)
N
1
σ2 ¿
N ∑ (xi−μ)( xi−μ)
i=1
N = number of observations = 10
μ = mean of the data
xi = individual observations
Mean
