Question

Stats help please?

Answer 1

@rational @kropot72

Answer 2

I recommend you start by converting every time value to seconds

Answer 3

then plot each (x,y) point

x = year
y = time in seconds

Answer 4

oh ok thanks @jim_thompson5910
so i have:
Year Winner, Country Time

1932 Helene Madison, USA 328.5 seconds
1936 Rie Mastenbroek, HOL 326.4 seconds
1948 Ann Curtis, USA 317.8 seconds
1952 Valeria Gyenge, HUN 312.1 seconds
1956 Lorraine Crapp, AUS 294.6 seconds
1960 Chris von Saltza, USA 290.6 seconds
1964 Ginny Duenkel, USA 283.3 seconds
1968 Debbie Meyer, USA 271.8 seconds
1972 Shane Gould, AUS 259.4 seconds
1976 Petra Thumer, E. Ger 249.9 seconds
1980 Ines Diers, E. Ger 248.8 seconds
1984 Tiffany Cohen, USA 247.1 seconds
1988 Janet Evans, USA 243.9 seconds
1992 Dagmar Hase, GER 247.2 seconds
1996 Michelle Smith, IRE 247.3 seconds

Answer 5

what kind of calculator do you have?

Answer 6

I use desmos most of the time but I have a ti-84 graphing calculator that i can use too @jim_thompson5910

Answer 7

I don't think desmos can handle linear regression, so let's use the TI84

Answer 8

enter the data into L1 and L2 of your stats tables

Answer 9

ok

Answer 10

When I'm entering the numbers in I'm getting an error message so i think I'm doing something wrong, i just pressed L1 and then put in all the numbers separating them with a comma

Answer 11

hit the stat button

Answer 12

then hit edit to get into the list edit mode

Answer 13

oops yea i fixed it sorry, i put the numbers in the L1 and L2 columns

Answer 14

ok, now hit "2nd" then the "0" key to bring up the catalog

Answer 15

scroll down to "diagnosticOn"

Answer 16

ok

Answer 17

next, hit the "stat" key

then scroll to the right one time to get to the "calc" menu and then scroll down to "linreg(ax+b)"

Answer 18

ok im there

Answer 19

what do you see come on the screen?

Answer 20

linreg(ax+b)
Xlist:L1
Ylist:L2
FreqList:
Store RegEQ:
Calculate

Answer 21

ok scroll down to calculate and hit enter

Answer 22

ok now it says:
linreg
y=ax+b
a= -1.559264359
b=3344.882376

Answer 23

nothing about the correlation coefficient r?

Answer 24

nope

Answer 25

this is what I get

Answer 26

of course, the diagnostic has to be on for r and r^2 to show up

Answer 27

hmm i hit diagOn when you said to so i don't know why my doesn't say that

Answer 28

did you see this?

Answer 29

yep

Answer 30

strange

Answer 31

well luckily we don't need r right now, but it's always nice to know how to find it. Maybe resetting the calculator will make it work?

but anyways, the linear regression equation is y = -1.559264359x + 3344.882376

plug in x = 1970 and evaluate to get the predicted winning time

Answer 32

ok i got 273.1315888

Answer 33

same here

Answer 34

273.1315888/60 = 4.55219314666667

0.55219314666667*60 = 33.1315888000002

So I'm getting 4 minutes, 33.13 seconds
or 4 minutes, 33.1 seconds

Answer 35

ok thanks, 4:33.2 is the closest answer i have so i think its right, thanks so much!

Answer 36

probably rounding error somewhere? but yeah that sounds right

Answer 37

what other choices does it mention?

Answer 38

Oh i got it right but it said 4:43.1, 4:34.2, 4:32.6

Answer 39

I see