1- A strong linear relationship (r = 0.97) exists between the two variables x and y in the table. The equation of the least squares line is y = 15.75 - 0.55x. For what values of x should we use this equation to make predictions?
x 5 7 8 10 11 12
y 5.5 8 8 9 10 11
A) Any positive value of x
B) Values of x less than or equal to 12
C) Values of x less than or equal to 5
D) Values of x between 5 and 12 inclusive
2-A survey of ages of children at a skate park produced the following results summarized in the frequency table:
Age Frequency
10 2
11 4
12 6
14 8
20 5
How many children were in the skate park?
What is the median age of children in the skate park?
What is the modal (mode) age of the children in the skate park?
What is the range value of the ages of children in the skate park?
If a birthday party of 5 children who were 10 years old came into the park, which of the following statistics would change? Type yes, or no.
median ?
mode ?
range ?
What percent of children in the skate park were less than 12 years of age? %
3- In two statistics classes, the same final exam was given and yielded the following results:
10:00am class: x-bar = 72, s = 10
11:00am class: x-bar = 67, s = 6
John, in the 10:00am class, scored 62 and Paul, in the 11:00am class, also scored 62.
Calculate John's z-score, round to 3 decimal places: (enter as 0.xxx)
Calculate Paul's z-score, round to 3 decimal places: (enter as 0.xxx)
Did John or Paul have a better relative standing in his respective class?