Question

In a study of academic procrastination, it was determined that for a random sample of 18 undergrad students at a mid-size public university, the mean time spent studying for the final exam in an intro statistics course was 7.74 hours with a standard deviation of 3.40 hours. What is the point estimate of the mean final exam study time for all undergrad students?

In a study of academic procrastination, it was determined that for a random sample of 18 undergrad students at a mid-size public university, the mean time spent studying for the final exam in an intro statistics course was 7.74 hours with a standard deviation of 3.40 hours. To a 90% confidence interval for the mean time spent studying for the intro statistics final exam for all undergrad students, the critical value needed would be ________.

In a study of academic procrastination, it was determined that for a random sample of 18 undergrad students at a mid-size public university, the mean time spent studying for the final exam in an intro statistics course was 7.74 hours with a standard deviation of 3.40 hours. Construct a 90% confidence interval for the mean time spent studying for the intro statistics final exam.

A random sample of 526 U.S. businesses found that 137 of the 526 businesses had fired workers for misuse of the Internet. The point estimate of the proportion of U.S. businesses who have fired workers for misuse of the Internet is __________.

A random sample of 526 U.S. businesses found that 137 of the 526 businesses had fired workers for misuse of the Internet. Compute a 98% confidence interval for the proportion of all U.S. businesses who have fired workers for misuse of the Internet. The margin of error for this confidence interval would be ________.

A simple random sample of n = 250 is drawn from a population with a standard deviation of 312. From the sample we determine the mean is 1500. In order to compute a confidence interval for the population mean we would use which of the following to compute the margin of error?

A new type of fertilizer is being tested on a plot of land in an orange grove, to see whether it increases the amount of fruit produced. The mean number of pounds of fruit on this plot of land with the old fertilizer was 400 pounds.Agriculture scientists believe that the new fertilizer may increase the yield. State the appropriate null and alternative hypotheses.

According to FICO the mean credit score is 703.5. A credit analyst wondered whether high income individuals (income over $100K per year) had higher credit scores. The analyst obtained a random sample of 40 high-income individuals and determined the mean credit score to be 714.2 with a standard deviation of 53.2. Calculate the test-statistic for a test of H0: μ ≤ 703.5 versus H1: μ > 703.5. The test statistic value (rounded to 2 decimal places) is ________.

According to the Centers for Disease Control (CDC), 15.2% of American adults experience migraine headaches. Stress is a major contributor to the frequency and intensity of headaches. A massage therapist feels that she has a technique that can reduce the frequency and intensity of migraines. A random sample of 500 American adults participate in the massage therapist’s program and 65 report experiencing migraines. Does this sample provide evidence that the proportion of American adults who experience migraines is reduced by the massage therapist’s program? Calculate the test-statistic for a test of Ho: p ≥ 0.152 versus H1: p < 0.152. The test statistic (rounded to 2 decimal places) is ______.

Answer #1

1. In a study of academic procrastination, it was determined
that for a random sample of 16 undergrad students at a mid-size
public university, the mean time spent studying for the final quiz
in an intro statistics course was 7.74 hours with a standard
deviation of 3.40 hours. Suppose we wish to compute a 95%
confidence interval for the mean time spent studying for the intro
statistics final quiz by all students. The margin of error for this
confidence interval...

In a study of academic procrastination, the authors of a paper
reported that for a sample of 421 undergraduate students at a
midsize public university preparing for a final exam in an
introductory psychology course, the mean time spent studying for
the exam was 7.54 hours and the standard deviation of study times
was 3.40 hours. For purposes of this exercise, assume that it is
reasonable to regard this sample as representative of students
taking introductory psychology at this university....

In a study of academic procrastination, the authors of a paper
reported that for a sample of 411 undergraduate students at a
midsize public university preparing for a final exam in an
introductory psychology course, the mean time spent studying for
the exam was 7.44 hours and the standard deviation of study times
was 3.30 hours. For purposes of this exercise, assume that it is
reasonable to regard this sample as representative of students
taking introductory psychology at this university....

In a study of academic procrastination, the authors of a paper
reported that for a sample of 421 undergraduate students at a
midsize public university preparing for a final exam in an
introductory psychology course, the mean time spent studying for
the exam was 7.44 hours and the standard deviation of study times
was 3.30 hours. For purposes of this exercise, assume that it is
reasonable to regard this sample as representative of students
taking introductory psychology at this university....

Consider a small population consisting of the 100 students
enrolled in an introductory statistics course. Students in the
class completed a survey on academic procrastination. The average
number of hours spent procrastinating when they should be studying,
per exam, by all students in this course is 4 hours with a standard
deviation of 2 hours. The distribution of amount of time students
spend procrastinating is known to be normal. (a) Identify the value
(in hours) of the population mean. 4...

Researchers have collected data from a random sample of six
students on the number of hours spent studying for an exam and the
grade received on the exam as given in Table 6.5.
Table 6.5
Observation
Grade
Number of Hours Studying
1
85
8
2
73
10
3
95
13
4
77
5
5
68
2
6
95
12
f) Find and interpret a 99% confidence interval for the mean
grade of all individuals who spend 10 hours studying.

The student academic group on a college campus claims that
freshman students study at least 2.5 hours per day, on average. One
Introduction to Statistics class was skeptical. The class took a
random sample of 30 freshman students and found a mean study time
of 137 minutes with a standard deviation of 45 minutes. If α = 0.01
(or 99% confidence level), is the student academic group’s claim
correct?

A questionnaire about study habits was given to a random sample
of students taking a large introductory stats class. The sample of
35 students reported that they spent an average of 115 minutes per
week studying stats. Assume that the standard deviation is 40
minutes.
A) Give a 95% confidence interval for the mean time spent
studying stats by students in this class.
B) Is it true that 95% of the students in the class have weekly
studying times that...

In
a random sample of 23 people aged 18-24, the mean amount of time
spent using the internet is 45.1 hours per month with a standard
deviation of 28.4 hours per month. Assume that the amount of time
spent using the internet in this age group is normally distributed.
1. if one were to calculate a confidence interval for the
population mean, would it be a z or t confidence interval? use the
flow chart to explain your answer.
2....

As part of his class project, a Statistics student took a random
sample of 50 college students and recorded how many hours a week
they spent on the Internet. The sample reveals an average of 6.9
hrs. Calculate the 90% confidence Interval for average Internet
usage among college students. Assume that the standard deviation of
Internet usage for college students is 4.5 hrs/week. Answer
1&2
1) A) E =1.58 B) E = 2.02 C) E =1.05 D) E = 2.58...

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