Students Born in USA

MEAN GPA: 3.05 STD DEVIATION: .511

MEAN AGE: 27 STD DEVIATION: 10

MEAN HOURS SPEND ON HW: 8.50 STD DEVIATION: 4.72

STUDENTS BORN OUTSIDE USA

MEAN GPA: 3.26 STD DEVIATION: .428

MEAN AGE: 31 STD DEVIATIONS: 10.5

MEAN HOURS SPENT ON HW: 14.13 STD DEVIATION: 10.4

1. If one student is randomly selected from the USA born group, find the probability of getting someone with a GPA greater than 3.88.

2. If one student is randomly selected from the Non-USA born group, find the probability of getting someone with a GPA greater than 3.88.

3. If one student is randomly selected from the USA born group, find the probability of getting someone between the ages of 20 and 25. 4. If 9 students are randomly selected from the Non-USA born group, find the probability that their mean age is between 22 and 37. 5. If 25 students are randomly selected from the USA born group, find the probability that their mean GPA is between 2.50 and 3.50.

Listed below are student evaluation ratings of​ courses, where a rating of 5 is for​ "excellent." The ratings were obtained at one university in a state. Construct a confidence interval using a 99​% confidence level. What does the confidence interval tell about the population of all college students in the​ state?

3.5​, 2.8​, 3.9​, 4.6​, 3.1​, 4.4​, 3.5​, 4.6​, 4.8​, 4.3​, 4.3​, 3.9​, 3.1​, 3.8​, 3.9

What is the confidence interval for the population mean mu​? ​(Round to two decimal places as​ needed.)

What does the confidence interval tell about the population of all college students in the​ state? Select the correct choice below​ and, if​ necessary, fill in the answer​ box(es) to complete your choice.

A. The results tell nothing about the population of all college students in the​ state, since the sample is from only one university.

B. We are 99​% confident that the interval from nothing to nothing actually contains the true mean evaluation rating. ​(Round to one decimal place as​ needed.)

C. We are confident that 99​% of all students gave evaluation ratings between nothing and nothing. ​(Round to one decimal place as​ needed.)

Astronauts often report episodes of disorientation as they move around the zero-gravity spacecraft. to compensate, crew members rely heavily on visual information to establish top-down orientation. An empirical study was conducted to asses the potential of using color brightness as a body orientation cue. 90 students at a specific university were randomly selected. They recline on their backs in the dark and were disorientated when postponed on a rotating platform under a slowly rotating disk that filled their entire field of vision. Half the disk was painted with a brighter level of color than the other half. The students were asked to say "stop" when they believed they were right side up. The brightness level of the disc was recorded. Of the 90 students 58 selected the brighter color level.

1) describe the parameter of interest in this study

2) calculate the parametric 90% confidence interval, checking any relevant conditions

3) interpret the interval from the previous part in the context of the problem

4) explain what is meant by 90% confidence

5) can we infer that a majority of all changes students would select brighter color levels as a body orientation cue? Explain why or why not.

Listed below are student evaluation ratings of​ courses, where a rating of 5 is for​ "excellent." The ratings were obtained at one university in a state. Construct a confidence interval using a 99​%

confidence level. What does the confidence interval tell about the population of all college students in the​ state?

4.0​, 3.0​,4.1​,4.8​, 3.0​ ,4.3​ ,3.7​ ,4.9​, 4.2​, 4.2​ ,4.1​ ,3.9 ​,3.4 ​,4.0​, 4.0

What is the confidence interval for the population mean μ​?

_____<μ<____?

​(Round to two decimal places as​ needed.)

What does the confidence interval tell about the population of all college students in the​ state? Select the correct choice below​ and, if​ necessary, fill in the answer​ box(es) to complete your choice.

A.We are 99​% confident that the interval from____ to____ actually contains the true mean evaluation rating.

​(Round to one decimal place as​ needed.)

B.We are confident that 99​% of all students gave evaluation ratings between _____ and______?

​(Round to one decimal place as​ needed.)

C.The results tell nothing about the population of all college students in the​ state, since the sample is from only one university.

A study was designed to compare the attitudes of two groups of nursing students towards computers. Group 1 had previously taken a statistical methods course that involved significant computer interaction. Group 2 had taken a statistic methods course that did not use computers. The students' attitudes were measured by administering the Computer Anxiety Rating Scale (CARS). A random sample of 12 nursing students from Group 1 resulted in a mean score of 47.5 with a standard deviation of 7.8 . A random sample of 15 nursing students from Group 2 resulted in a mean score of 54.7 with a standard deviation of 5.4 . Can you conclude that the mean score for Group 1 is significantly lower than the mean score for Group 2? Let   μ1 represent the mean score for Group 1 and μ 2  represent the mean score for Group 2. Use a significance level of α=0.1 for the test. Assume that the population variances are equal and that the two populations are normally distributed.

Step 2 of 4 :

Compute the value of the t test statistic. Round your answer to three decimal places.

A study was designed to compare the attitudes of two groups of nursing students towards computers. Group 1 had previously taken a statistical methods course that involved significant computer interaction. Group 2 had taken a statistic methods course that did not use computers. The students' attitudes were measured by administering the Computer Anxiety Rating Scale (CARS). A random sample of 9 nursing students from Group 1 resulted in a mean score of 46.1 with a standard deviation of 5.9. A random sample of 14 nursing students from Group 2 resulted in a mean score of 56.3 with a standard deviation of 7.9. Can you conclude that the mean score for Group 1 is significantly lower than the mean score for Group 2? Let μ 1 represent the mean score for Group 1 and μ 2 represent the mean score for Group 2. Use a significance level of α= 0.1 for the test. Assume that the population variances are equal and that the two populations are normally distributed. Step 3 of 4 : Determine the decision rule for rejecting the null hypothesis H 0 . Round your answer to three decimal places.

1. Zoo officials are interested in determining the predicted weight of newborn giraffes. A random sample of 8 newborn giraffes’ weights were obtained. Assume that newborn giraffes’ weights are Normally distributed. From the sample, the mean weight was 137 lbs and the standard deviation was 12.5 lbs. Construct and interpret a 99% confidence interval for the population mean weight of all newborn giraffes.

2. Students in one sample were shown positive evaluations of an instructor and the students in a second sample were shown negative evaluations of an instructor. Then, all subjects were shown the same lecture video given by the same instructor. They were then asked to rate the instructor using three questions and a summary rating was calculated. Is there evidence that the students’ rating was influenced by the prior student evaluations? Perform a hypothesis test with a 5% level of significance to determine if students gave the instructor a higher score if they were shown positive evaluations versus negative evaluations. Assume that both samples come from Normally distributed populations.

df=46

steps:

i.

ii.

iii.

PART I

Suppose that the mean and standard deviation of the scores on a statistics exam are 78 and 6.11, respectively, and are approximately normally distributed. Calculate the proportion of scores above 74.

PART II

When students use the bus from their dorms, they have an average commute time of 9.969 minutes with standard deviation 3.9103 minutes. Approximately 27.23% of students reported a commute time greater than how many minutes? Assume the distribution is approximately normal.

PART III

When students use the bus from their dorms, they have an average commute time of 9.945 minutes with standard deviation 3.2476 minutes. Approximately 42.21% of students reported a commute time less than how many minutes? Assume the distribution is approximately normal.

A study was designed to compare the attitudes of two groups of nursing students towards computers. Group 1 had previously taken a statistical methods course that involved significant computer interaction. Group 2 had taken a statistic methods course that did not use computers. The students' attitudes were measured by administering the Computer Anxiety Rating Scale (CARS). A random sample of 11 nursing students from Group 1 resulted in a mean score of 53.1 with a standard deviation of 4.4. A random sample of 17 nursing students from Group 2 resulted in a mean score of 63 with a standard deviation of 3. Can you conclude that the mean score for Group 1 is significantly lower than the mean score for Group 2? Let μ1 represent the mean score for Group 1 and μ2 represent the mean score for Group 2. Use a significance level of α=0.01 for the test. Assume that the population variances are equal and that the two populations are normally distributed. Step 3 of 4 : Determine the decision rule for rejecting the null hypothesis H0. Round your answer to three decimal places.

1. Educational economists are trying to determine whether preschool head-start programs are beneficial in improving reading proficiency.  To test the effect they conducted a lottery with 100 parents of preschool kids who indicated that they wanted to send their kids to a head-start program but couldn’t afford it.  The researchers randomly selected 36 students from the 100 and gave them a voucher for preschool.  All 36 of these students attended a head-start program.  After attending head-start, and then 3 years of elementary school, all 100 students were administered a reading test.  Of the 36 who attended head-start, 29 passed the test.  Of the 64 who did not attend head-start, 48 passed.
   1. Using a significance level of 5%, conduct a hypothesis test to determine whether the head-start program affected the proportion of students who successfully pass the reading test. (5)

2. Based on your response to a., does this mean that we can state definitively that there really is or isn’t an effect of preschool on reading ability after grade 3?  I am interested in having you explain using the statistical interpretation of hypothesis testing (as opposed to critiquing the experimental design. (5)