It is claimed that automobiles are driven on
average more than 20,000 kilometers per year. To...
It is claimed that automobiles are driven on
average more than 20,000 kilometers per year. To test
this claim, 100 randomly selected automobile owners
are asked to keep a record of the kilometers they travel.
Would you agree with this claim if the random sample
showed an average of 23,500 kilometers and a standard
deviation of 3900 kilometers? Use a P-value in your
conclusion.
but construct a 99% confidence interval
Suppose that a study shows that an electric bike is driven
23,500 km/year on average and...
Suppose that a study shows that an electric bike is driven
23,500 km/year on average and has a standard deviation of 3900 km.
Assume that the measurements’ distribution is approximately
normal.
a) Calculate the 3rd quartile.
b) Solve for the probability that a randomly selected electric
bike is driven between 10,000 and 20,000 km per year.
Suppose you have selected a random sample of ?=14 measurements
from a normal distribution. Compare the...
Suppose you have selected a random sample of ?=14 measurements
from a normal distribution. Compare the standard normal ? values
with the corresponding ? values if you were forming the following
confidence intervals.
(a) 90% confidence interval
z=
t=
(b) 95% confidence interval
z=
t=
(c) 98% confidence interval
?=
t=
2) A confidence interval for a population mean has length
20.
a) Determine the margin of error.
b) If the sample mean is 58.6, obtain the confidence
interval.
Confidence interval: ( ,...
1.The following data shows test scores for a sample of
statistics students.
83, 64, 84, 76,...
1.The following data shows test scores for a sample of
statistics students.
83, 64, 84, 76, 84, 54, 75, 59, 70, 63, 80, 84, 73, 68, 52, 65,
90, 52, 95, 36, 78, 61, 59, 84, 95, 47, 87
a. Find a 95% confidence interval for the mean test score for
all students.
b. Interpret this 95% CI for the population mean.
c. What is the margin of error?
2. A recent national survey found that high school students
watched...
1. Canadians are becoming more conscious of the importance of
good nutrition, and some researchers believe...
1. Canadians are becoming more conscious of the importance of
good nutrition, and some researchers believe that we may be
altering our diets to include less red meat and more fruits and
vegetables. To test this theory, a researcher decides to select
hospital nutritional records for subjects surveyed 10 years ago and
to compare the average amount of beef consumed per year to the
amounts consumed by an equal number of subjects she will interview
this year. She knows that...
The Federal Election Commission collects information about
campaign contributions and disbursements for candidates and
political committees...
The Federal Election Commission collects information about
campaign contributions and disbursements for candidates and
political committees each election cycle. During the 2012 campaign
season, there were 1,619 candidates for the House of
Representatives across the United States who received contributions
from individuals. The table below shows the total receipts from
individuals for a random selection of 40 House candidates rounded
to the nearest $100.
$3,600
$1,243,900
$10,900
$385,200
$581,500
$7,400
$2,900
$400
$3,714,500
$632,500
$391,000
$467,400
$56,800
$5,800
$405,200
$733,200...
In a study of academic procrastination, it was determined that
for a random sample of 18...
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...