Checkpoint 2 of 3 10 MC + 2 Short Answer Covers Lessons 8-14

Checkpoint 2

Spread, Comparison and Bivariate Data. Assess your understanding of range, IQR, box plots, standard deviation, comparing distributions, scatter plots, correlation and lines of best fit.

Instructions: Complete all questions. For multiple choice, select one answer and click Check. For short answer, show all working. Your responses are saved automatically.

Section A - Multiple Choice

2 marks each. Select the best answer.

2 marks For the ordered data 2, 4, 6, 8, 10, 12, 14, the interquartile range is:

4 6 8 12

2 marks A box plot does NOT show:

The median The quartiles Individual data values The range

2 marks A small standard deviation indicates that:

Data is widely spread Data is clustered near the mean The mean is small There are many outliers

2 marks Class A has mean = 72, IQR = 8. Class B has mean = 68, IQR = 15. We can conclude:

Class A performed worse on average Class B has more consistent scores Class A scored higher on average with less variability The classes performed equally

2 marks On a scatter plot, points trending downward from left to right indicate:

Positive correlation Negative correlation No correlation Perfect correlation

2 marks A line of best fit with gradient −2 and y-intercept 10 has equation:

y = 10x − 2 y = −2x + 10 y = 2x + 10 y = −2x − 10

2 marks Interpolation is more reliable than extrapolation because:

It uses a calculator It is within the range of observed data It always gives whole numbers It requires less data

2 marks The standard deviation can never be:

Zero Positive Negative A decimal

2 marks A longer upper whisker than lower whisker on a box plot indicates:

Negative skew Positive skew Symmetric distribution No outliers

2 marks Study time and exam scores have a strong positive correlation. This means:

Studying more causes higher scores Students who study more tend to score higher All students who study a lot get perfect scores Higher scores cause more studying

Section B - Short Answer

Show all working. 5 marks each.

Question 11

5 marks Apply / Analyse

The ages of people at a concert are summarised below:

Minimum = 12, Q1 = 18, Median = 24, Q3 = 32, Maximum = 55

(a) Draw a box plot for this data. (2 marks)

(b) Calculate the interquartile range. (1 mark)

Question 12

5 marks Analyse / Evaluate

A survey recorded the number of hours 8 students spent studying and their test scores:

Hours	1	2	3	4	5	6	7	8
Score	45	52	58	60	68	72	78	85

(a) Describe the correlation between study time and test scores. (1 mark)

(b) Estimate the equation of the line of best fit by eye. (2 marks)

(c) Use your line to predict the score for a student who studies 4.5 hours. Is this interpolation or extrapolation? (2 marks)

I have completed Checkpoint 2 and checked my answers.