Question

please help, giving medal!
A student is assessing the correlation between the average number of hours of internet browsing and average score on a math test for the students of a class. The table below shows the data:


Number of hours of internet browsing
(x) 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5
Score on math test
(y) 95 94 93 92 91 90 89 87 86 85

Answer 1

Part A: Is there any correlation between the average number of hours of internet browsing and average score on the math test for the students of the class? Justify your answer. (4 points)

Part B: Write a function which best fits the data. (3 points)

Part C: What does the slope and y-intercept of the plot indicate? (3 points)

Answer 2

what kind of calculator do you have?

Answer 3

i think my calculator does almost everything, why?

Answer 4

is it a TI calculator?

Answer 5

im not sure, if you give me an example on what to type ill tell you if i can or not.

Answer 6

like TI83 or TI84

Answer 7

i dont even know what that means. what kind of math is that?

Answer 8

I'm just asking about the model of the calculator

like what type it is

Answer 9

im really not sure, i use both my phone , scientific, and a online calculator that i pay for.

Answer 10

ok you can use free calculators to get the job done

let me find one

Answer 11

i use mathway

Answer 12

is there a typo for the y's?
it went from 89 to 87

Answer 13

you can use this calculator

http://www.alcula.com/calculators/statistics/linear-regression/

Answer 14

no there is no typo i just double checked

Answer 15

you type in each ordered pair on its own line
but you don't use parenthesis

Answer 16

Sample size: 10
Mean x (x̄): 2.25
Mean y (ȳ): 90.2
Intercept (a): 95.272727272727
Slope (b): -2.2545454545455
Regression line equation: y=95.272727272727-2.2545454545455x

Answer 17

correct

Answer 18

if you were to click on "Correlation coefficient " it will give you the Correlation coefficient

Answer 19

that'll help you answer part A

Answer 20

and the equation you got will help answer part B

Answer 21

Correlation coefficient (r): -0.9963777371265
how would i round it?

Answer 22

3 or 4 decimal places is good enough I think

Answer 23

I'd do 4 decimal places

Answer 24

ok i got A, so how do i do B?

Answer 25

so that suggest we have very strong negative correlation

basically as "Number of hours of internet browsing" goes up, "Score on math test" goes down

that makes sense to a certain point assuming these people are browsing facebook or youtube or something (that doesn't help them study). However, you can easily use the internet to do research and take notes, etc

Answer 26

the equation you get will help you get the function

Answer 27

just replace y with f(x) and that's all there is to it

Answer 28

F(x)=95.272727272727-2.2545454545455x

should i round the numbers

Answer 29

yeah I'd do 3 decimal places

y = -2.255x + 95.273

and I moved the terms

Answer 30

then replace y with f(x)

f(x) = -2.255x + 95.273

Answer 31

ok thanks and what do i do for c

Answer 32

how do you think you should answer C?

Answer 33

in other words, what does the slope mean? the y-intercept?

Answer 34

it the vertical line on a graph i think

Answer 35

look back at the graph that calculator produces

Answer 36

ntercept (a): 95.272727272727
Slope (b): -2.2545454545455

Answer 37

do you see the visual graph (scatter plot + regression line)?

Answer 38

yes

Answer 39

http://www.alcula.com/calculators/statistics/linear-regression/linear-regression-image.php?n=1

Answer 40

notice how it's sloping downward, which is because of the negative slope

Answer 41

yes

Answer 42

so that means we have negative correlation

as time on the internet goes up, scores go down

Answer 43

that's what it means to have negative correlation (and a negative slope on the regression line)

Answer 44

the y-intercept tells you the approximate score you expect when x = 0

so basically the score when you spend 0 hours on the internet

Answer 45

ok thank you so much

Answer 46

you're welcome