Question

The paint used to make lines on roads must reflect enough light to be clearly visible at night. Let μ denote the true average reflectometer reading for a new type of paint under consideration. A test of H0: μ = 20 versus Ha: μ > 20 will be based on a random sample of size n from a normal population distribution. What conclusion is appropriate in each of the following situations? (Round your P-values to three decimal places.)

(a) n = 14, t = 3.1, α = 0.05
P-value =

(b) n = 10, t = 1.8, α = 0.01
P-value =

(c) n = 28, t = −0.6
P-value =

Answer 1

@PrincessVentures

Answer 2

so the problem here is that my table isn't very accurate... Do you know how to use R studio?

Answer 3

I can take a pic of the table if you want...

Answer 4

Please do. :)

Answer 5

sorry I lost connection... let me take a pic

Answer 6

@PrincessVentures

Answer 7

If you don't know it's okay. I can ask my instructor tomorrow.

Answer 8

@AravindG can you help me?

Answer 9

Please wait. The table is loading.

Answer 10

Your t table is different from mine. Mine has the division of two-tailed alpha and one tailed alpha.

Answer 11

hmmm let me check something

Answer 12

Nope that is right.

Answer 13

so this is what I have for part a 0.001<P-value<0.005

Answer 14

I'll leave this to @PrincessVentures . My pc becomes unresponsive when I try to open image of size greater than 3 mb. Sorry.

Answer 15

The value is between 0.001 and 0.005 however my numbers on the table are not very accurate. Is there a way to read it to a more accuarate decimal?

Answer 16

For example, you are given alpha=0.05. Your d.f is n-1;13
Since it is right-skewed (μ > 20), you get the +t
Find d.f 13 and with the alpha 0.05 in your table.

Answer 17

ohhh wow it's 1.771

Answer 18

I must be reading the table wrong...

Answer 19

Openstudy is going loco. Can't access properly. :(

Answer 20

Anyway, you got it right. :D

Answer 21

i can see what yo are typing clearly

Answer 22

Do not reject the null hypothesis. There is sufficient evidence to conclude that the new paint has a reflectometer reading higher than 20.
Reject the null hypothesis. There is sufficient evidence to conclude that the new paint has a reflectometer reading higher than 20.
Reject the null hypothesis. There is not sufficient evidence to conclude that the new paint has a reflectometer reading higher than 20.
Do not reject the null hypothesis. There is not sufficient evidence to conclude that the new paint has a reflectometer reading higher than 20.

Answer 23

from my p value = 1.771 which of these are correct ?

Answer 24

our null = mu = 20 the probablility is 1.71 which is telling us that the new paint has a reflectometer reading higer than 20. The conceptual part is confusing me.

Answer 25

This is hypothesis testing. You familiar?

Answer 26

It is actually confusing me a bit too. You should just ask your professor tomorrow, I know that he will help you. I am familiar with it but I forgot already. I will try to recall. :) Will tell you if I remember.

Answer 27

The math is easy just the concept is confusing...

Answer 28

how do I find the pvalue is alpha isn't given?

Answer 29

You need to have the t-value, sample size, and the tail. You look at the t table what two values the value of t falls between. Depending on the tail test, you look up to the row labeled one tail and find the two alpha values Hence, the P-value would be contained in the interval of the tail values.
Sorry, I can't help anymore because openstudy keeps on showing No Internet Connection and if I refresh, goes to an ERROR webpage. I hope this helps! Good luck. :)

Answer 30

well the number looks to between 1.313 and 1.711 so how do I figure out the true number