Download Assessing P-Value Interpretations Name: solution

Assessing P-Value Interpretations
Name:
solution
Below are your interpretations of the p-value from the significance test that you carried out. Now it’s
time for you to assess the quality of each interpretation. Below each number, assign a rating (from 0 to
10) to each interpretation. As before, I’ll calculate the correlation between your ratings and my own
ratings, and your score for this activity will be based on that correlation.
One-Sample T: Age
Test of mu = 240 vs > 240
Variable
Age
N
24
Mean
247.29
StDev
17.09
SE Mean
3.49
95% Lower
Bound
241.31
T
2.09
P
0.024
I assigned scores based correct calculations, on stating the null hypothesis (with units), then assuming
the null hypothesis giving the probability (p-value) that the statistic x (sample mean) for an SRS of size
n would have the given value (or greater), how the p-value affects the evidence for/against Ho, and your
conclusion (alternate hypothesis).
1.
We can assume that our data is statistically significant using a 0.05 significance level, and given
our p-value is 0.018. Therefore there is good evidence against the null hypothesis that the mean
population of age for all Wittenberg students is 240 months. With a population mean of 240 and
and SRS if size n=24 having a sample mean of 240 or greater would occur less than
approximately 2% of the time.
[8]
wrong test (z- test figures)!
2.
The t-test revealed that t=2.09 and P=.024. This means that a student
taken at random from the population of Wittenberg students is 2.4% likely
to be greater than 240 months old.
[2]
figures are correct but interpretation is all wrong; it’s not an individual, it’s the mean
3.
The p-value for a SRS of n=24, from a population of Wittenberg Students that has a mean
age of 240 months, is 0.024. This means that if the mean age of the Witt Student
population is indeed 240 months then the mean value for the SRS has a only
2.4% probability of being found on the population curve. This is significant value when
looking at a 0.05 significance level in disproving the null hypothesis.
[7]
p-value for what? What is x ? – confusing (“found on population curve”?)
4.
The null hypothesis (H0: U=240) can be rejected given that the p= 0.024.
[4]
no statement of null hypothesis or meaning of p-value. What is
5.
By performing a t-test, it revealed that when µ=> 240 the probability is 0.048 with a sample
population mean of 247.29, StDev. of 17.09, and a t value of 2.09. The probability tells us that
yes this vale is significant at the .5 level.
[3]
0.5 level? “when µ=> 240”? What is null hypothesis? Sample size?
x?
6.
The probability of getting x-bar for a SRS of Witt students of size n=24 which is +7.29 away
µ
from =5 would occur approximately 2% of the time. This is not good enough evidence to
reject the original hypothesis.
[6]
µ is 240 – not 5; awkwardly phrased; what is null hypothesis?
7.
2.4% of the time you will find the average age of students to be greater than 240 when the true
population mean is 240.
[2]
Confusing average age of students with sample mean; need to state null hypothesis
8.
The observed value of the statistics is z=0.43. A mean age greater than
240 months would occur about 33.6% if the population mean were 240 months.
This is not good evidence that the population mean is not 240 months at
any significant level.
[2]
Figure incorrect; need to state mean age of sample; need to state null
hypothesis
9.
The probability that age in months will be above 240 months is 0.048 (4.8%)
[0]
wrong figures; no null hypothesis stated; used 2-tail test!
10.
P=0.048. This means that if the the population mean was 240
the possiblity of getting this result would be 4.8%.
[4]
What is “this result”? Should be 1 tail test. What is
11.
P=.024. This means that a mean of 240 would only ocur about 2.4% of the time. This
would suggest that there is evidence against the null hypothesis.
[0]
??? State null hypothesis;
12.
we found our P-value equal to 0.950011
[0]
Context! No information given; wrong p-value
13.
If the null hypothesis is true, then you would get a sample mean equal to
or greater than 240 only 2.4% of the time. This is evidence against the
null hypothesis.
[4]
state sample size and value of
14.
Using this stats 127 class as a SRS of a population of all witt students, the p-value of the
data of ages in months is 0.048. This is statistically significant at the 0.05 significance
level, and therefore there is reason to reject the null hypothesis that the student's ages is
equal to 240 months
[5]
use 1 tail test; student’s mean age is equal to 240 month? What is x ?
x?
x ; state null hypothesis explicitly;