# Exam-Style Question on Correlation

## A mathematics exam-style question with a worked solution that can be revealed gradually

##### List Of QuestionsExam-Style QuestionMore Correlation QuestionsMore on this Topic

Question id: 663. This question is similar to one that appeared on an IB AA Higher paper in 2023. The use of a calculator is allowed.

A programmer recorded the number of web pages she had created since she had begun working for the Corney Content Creation Company. The following table shows the number of days, $$d$$, and the cumulative total number of web pages, $$p$$.

 Number of days $$(d)$$ 5 9 16 18 23 29 32 40 50 Number of pages $$(p)$$ 14 28 47 54 65 90 95 123 156

The value of Pearson's product moment correlation coefficient, $$r$$ for this data is 0.999 to three significant figures.

(a) The regression line of $$p$$ on $$d$$ for this data can be written in the form $$p=ad + b$$. Find the value of a and the value of b.

(b) Use your regression line to estimate the number of web pages created by day 45.

 The worked solutions to these exam-style questions are only available to those who have a Transum Subscription. Subscribers can drag down the panel to reveal the solution line by line. This is a very helpful strategy for the student who does not know how to do the question but given a clue, a peep at the beginnings of a method, they may be able to make progress themselves. This could be a great resource for a teacher using a projector or for a parent helping their child work through the solution to this question. The worked solutions also contain screen shots (where needed) of the step by step calculator procedures. A subscription also opens up the answers to all of the other online exercises, puzzles and lesson starters on Transum Mathematics and provides an ad-free browsing experience.

Drag this panel down to reveal the solution

The exam-style questions appearing on this site are based on those set in previous examinations (or sample assessment papers for future examinations) by the major examination boards. The wording, diagrams and figures used in these questions have been changed from the originals so that students can have fresh, relevant problem solving practice even if they have previously worked through the related exam paper.

The solutions to the questions on this website are only available to those who have a Transum Subscription.

Exam-Style Questions Main Page

Search for exam-style questions containing a particular word or phrase:

To search the entire Transum website use the search box in the grey area below.