A college entrance exam company determined that a score of 2222 on the mathematics portion of the exam suggests that a student i
1 answer:
Answer:
Yes, Students are scoring above 2222 on the math portion of the exam.
Step-by-step explanation:
We are given that a college entrance exam company determined that a score of 2222 on the mathematics portion of the exam suggests that a student is ready for college-level mathematics i.e., population mean is 22.
Null Hypothesis, :
= 22 {Students are scoring equal to 2222 on the math portion of the exam}
Alternate Hypothesis, :
> 22 {Students are scoring above 2222 on the math portion of the exam}
Also, a random sample of 150 students who completed this core set of courses results in a mean math score of 22.7 on the college entrance exam with a standard deviation of 3.93 i.e.;
Sample mean, = 22.7 and Sample standard deviation, s = 3.93
The Test statistics is given by;
Z = ~
Test Statistics = ~
= 2.1815
Since, we are not given with the significance level, so we assume it to be 5%. At 5% significance level t table gives critical value of 1.6578 at 149 degree of freedom. Since our test statistics is more than the critical value so we reject null hypothesis as our test statistics fall in the rejection region.
Therefore, we conclude that Students are scoring above 2222 on the math portion of the exam.
You might be interested in
Answer:
a)
If we compare the p value and using any significance level for example always
so we can conclude that we have enough evidence to FAIL to reject the null hypothesis, and we can say that we don't have significant differences between the two proportions.
b) We are confident at 99% that the difference between the two proportions is between
Step-by-step explanation:
Previous concepts and data given
A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".
The margin of error is the range of values below and above the sample statistic in a confidence interval.
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
represent the real population proportion of women age 18 to 30 agreed with the statement that a woman should have the right to a legal abortion for any reason
represent the estimated proportion of women age 18 to 30 agreed with the statement that a woman should have the right to a legal abortion for any reason
is the sample size for A
represent the real population proportion for women age 58 to 70 agreed with the statement that a woman should have the right to a legal abortion for any reason
represent the estimated proportion of women age 58 to 70 agreed with the statement that a woman should have the right to a legal abortion for any reason
is the sample size required for B
represent the critical value for the margin of error and for the statisitc
The population proportion have the following distribution
Part a
We need to conduct a hypothesis in order to check if the proportion are equal, the system of hypothesis would be:
Null hypothesis:
Alternative hypothesis:
We need to apply a z test to compare proportions, and the statistic is given by:
(1)
Where
Calculate the statistic
Replacing in formula (1) the values obtained we got this:
Statistical decision
Since is a two sided test the p value would be:
If we compare the p value and using any significance level for example always
so we can conclude that we have enough evidence to FAIL to reject the null hypothesis, and we can say that we don't have significant differences between the two proportions.
Part b
The confidence interval for the difference of two proportions would be given by this formula
For the 99% confidence interval the value of and
, with that value we can find the quantile required for the interval in the normal standard distribution.
And replacing into the confidence interval formula we got:
And the 99% confidence interval for the difference of proportions would be given (-0.188;0.226).
We are confident at 99% that the difference between the two proportions is between