Answer:
1: 4
2: 2
3: 8
Step-by-step explanation:
Solution: Which statement about the scatter plot is true?
The correct answer is option A. As the number of weeks in class increases, the number of keyboarding mistakes decreases.
Explanation: From the scatter plot, we clearly see there exists a negative linear relationship between the number of weeks in class and the number of mistakes. And we know that if there exists a negative linear relationship between the two variables, then the values of two variables move in opposite direction. If the values of one variable goes up, the values of other variable go down. From the given scatter plot, we clearly see the number of mistakes goes down as the number of weeks in class increases. Therefore, the option A is correct
Standard Deviation, σ: 1.5
Count, N: 10
Sum, Σx: 15
Mean, μ: 1.5
Variance, σ2: 2.25
Steps
σ2 =
Σ(xi - μ)2
N
=
(0 - 1.5)2 + ... + (5 - 1.5)2
10
=
22.5
10
= 2.25
σ = √2.25
= 1.5
