NJSLA NJSLA Data Analysis and Statistics

Question 1

A student recorded the following test scores: 72, 85, 90, 68, 95, 80. What is the median score?

Accepted Answer

82.5

Answer

When the six scores are ordered (68, 72, 80, 85, 90, 95), the median is the average of the 3rd and 4th values: (80 + 85) / 2 = 82.5.

Question 2

Which measure of central tendency is most affected by an outlier?

Accepted Answer

Mean

Answer

The mean is most affected by outliers because it sums all values and divides by the count, so an extreme value shifts it significantly.

Question 3

A box plot shows a minimum of 10, Q1 of 20, median of 35, Q3 of 50, and maximum of 70. What is the interquartile range (IQR)?

Accepted Answer

30

Answer

The IQR equals Q3 minus Q1, so 50 − 20 = 30.

Question 4

A scatter plot shows points trending upward from left to right. This indicates which type of correlation?

Accepted Answer

Positive correlation

Answer

When both variables increase together and the points trend upward, the data shows a positive correlation.

Question 5

A survey of 200 students found that 60 prefer math. What percentage prefer math?

Accepted Answer

30%

Answer

60 divided by 200 equals 0.30, which is 30%.

NJSLA Exam Practice Test