Question

Given a dataset of n ordered pairs (each an (x,y)), how many degrees of freedom are there?

Answer 1

@whpalmer4

Answer 2

@agent0smith

Answer 3

Were we talking about a SAMPLE of size n, the number of degrees of freedom is generally n-1. Have to admit I'm not sure whether that same principle applies to sets of data points.

Answer 4

@mathmale

Answer 5

sorry hold on wong question.

Answer 6

Yhat= 10.5+8.2x

Answer 7

Can a pretest on mathematics skills predict success in a statistics course? The 55 students in an introductory statistics class took a pretest at the beginning of the semester. The least-squares regression line for predicting the score y on the final exam from the pretest score x was Yhat= 10.5+8.2x .The standard error of b was 0.38. Test the null hypothesis that there is no linear relationship between the pretest score and the score on the final exam against the two-sided alternative.

Answer 8

@mathmale

Answer 9

@whpalmer4

Answer 10

I very much regret not being able to be of help with this new problem either. I've looked up "standard error" on the 'Net and have come up with the following source of info:

https://www.google.com/search?q=standard+error&rlz=1C1CHFX_enUS461US461&oq=standard+error&aqs=chrome..69i57j0l5.2584j0j7&sourceid=chrome&espv=210&es_sm=122&ie=UTF-8

Where a homework problem like this one, the first of its kind I've seen posted on OpenStudy in two months, is involved, you'll find relatively few people who can help with this "hypothesis testing" and/or "two-sided alternative." My suggestion is that in the future you explain what you have already been able to do and what it seems to be that you need to learn/know to finish the problem. Just posting the problem without commentary leaves others wondering about where and how to get involved (unless they can and want to explain everything from scratch).

Answer 11

can you help me with another question? thanky ou !

Answer 12

A sprinter runs the 100 yard dash 4 separate times. His mean time in those 4 trials is 11 seconds with a standard deviation of s = 0.2 seconds. What is the standard error of the mean?

2.75 seconds

0.2 seconds

0.1 seconds

0.05 seconds

1 second

Answer 13

@nikato

Answer 14

@whpalmer4

Answer 15

@agent0smith

Answer 16

Your latest question appears considerably easier and more familiar to me than did the previous one.

Have you looked at that web site I told you about a few minutes ago? It'd be worth your while to go there to learn anything you may need to know about "standard error."

Here's the problem you've posted:

A sprinter runs the 100 yard dash 4 separate times. His mean time in those 4 trials is 11 seconds with a standard deviation of s = 0.2 seconds. What is the standard error of the mean?

Here n=4 (a very, very small sample size!)
If I understand this question correctly, the standard error is

S
------- ,
Sqrt(n)

where S is the sample standard deviation and n is the number of samples. I'm sure you can calculate that yourself.

Answer 17

C?

Answer 18

sorry D!

Answer 19

Suzy wants to assess the accuracy of a laboratory scale, and a standard weight is known to weigh 20 grams is repeatedly weighed. The scale readings are normally distributed with an unknown mean µ. Suppose you weigh the weight 9 times and obtain a mean weight of 20.005 grams and a standard deviation s = 0.003. Is this data strong evidence of bias in the scale?
Ho: u=20
Ha u does not equal 20

What are the appropriate degrees of freedom for this test?

8

9

10

20

64

Answer 20

Kenshin, I'd be happy to respond if you show me how you got your answer. Please don't ask "yes" or "no" or "right" or "wrong" questions.

Answer 21

Okay well i got it from what you have given me 0.2/2= 0.05

Answer 22

Thank you for sharing that. Looks like "D" is correct. Best wishes to you. Unfortunately, I need to sign off from OpenStudy now, as I've spent most of the day sitting in front of my computer!

Answer 23

okie dokie thank you!