Homework 2
Due May 18 at 11:59pm
Points 19
Questions 19
Time Limit None
Allowed Attempts 3
Available May 12 at 12am - May 18 at 11:59pm 7 days
Instructions
This assignment consists of 19 questions. Please answer every question prior to submitting your ass

Practice:
Question
Sampling error is the difference between the statistic and the _.
Population proportion
Parameter
Population standard deviation
None of the above
Question
Which is not a continuous random variable?
Length of an ECO 250 lecture
Wingspan

Question 3
A _ is defined as the probability that the interval estimate will include the population
parameter of interest, such as a mean.
Answer: Confidence interval
margin of error
confidence level
significance level
confidence interval
Question 4
A ran

1
Question 1
A _ sample is a sample in which each member of the population has a known, nonzero,
chance of being selected for the sample.
probability
systematic
simple random
convenience
Question 2
In _ sampling, we divide the population into mutually exc

1. The average weight of the entire batch of the boxes of cereal filled today was 20.15
ounces. A random sample of four boxes was selected with the following weights: 20.05,
20.56, 20.72, and 20.43. The sampling error for this sample is _. -0.29
2. A repo

1
Question 1
The purpose of generating a confidence interval for the mean is to provide an estimate for the
value of the population mean.
Answer: True
True
False
Question 2
When calculating a confidence interval for the mean using a sample size of 30 or m

Question 6 1 l 1 Pts
Calculate the variance of dataset A (treating the dataset as a
population).
63.9410 \
63.94 (with margin: 0.1)
Question 7 1 l 1 Pts
Based on your answer to question 6, what is the standard
deviation of dataset A?
8.0000 \
7.996 (wit

For question 5 to 8, suppose you roll a six sided dice three
times and count the number of times you roll a three or a six.
Question 5 1 I 1 pts
What is the probability that your count is 3?
0.0370
0.037 (with margin: 0.001)
Question 6 1 l 1 pts
What i

Question 3 1 I 1 Pts
What is the standard error of the sample means?
6.3250 I
6.325 (with margin: 0.05)
Question 4 O I 1 pts
What is the zscore for the mean of sample 2?
Correct Answers
You Answered
Correct Answers 0.269 (with margin: 0.01)

Question 14
What best describes the skewness of dataset B?
Highly rightskewed
Correct! 3 Roughly symmetrical
Highly leftskewed
Question 15 1 I 1 ts
Calculate the sample variance of dataset B.
28.6000 \
28.61 (with margin: 0.05)
Correct Answers

For questions 1 and 2, use the following distribution:
P00 0.3 0.3 0.2 0.1 0.1
X 1 2 3 4 5
Question 1 1 l 1 Pts
What is the mean of the distribution?
2.4000
2.4 (with margin: 0.0)
Question 2 1 I 1 Pts
What is the variance of the distribution?
1.6400
l C

Question 9 1 I 1 pts
Suppose you want to estimate the impact of fast food
consumption on health. You collect data by selecting 10
restaurants and surveying every customer in each of them on
a given day. This is an example of:
Convenience Sampling
Stratied

Which best describes the mode of dataset A?
Dataset A has modes of 5, 7, and 11.
Dataset A has no mode.
CONE! 4' Dataset A has a mode of 5.
Question 5 1 I 1 ts
What is the range of dataset A?
31.0000
31.0 cfw_with margin: 0.0)
Correct Answers

Question 2 1 / 1 Pts
Calculate the median of dataset A.
7.0000
7.0 (with margin: 0.0)
Given your previous responses, what is the skewness of
dataset A?
Correct Answers
the distribution of dataset A is symmetrical.
the distribution of Dataset A is l

For the questions 20 to 22 use the following:
The probability of event A is 0.2.
The probability of event B given that event A happens is 0.4.
The probability that event B happens given then event A
does not happen is 0.5.
Question 20 0 I 1 PB
What is the

Score for this attempt: 10 out of 10
Submitted May 16 at 1:45pm
This attempt took 3 minutes.
Question 1
1 / 1 pts
What type of data is the following variable.
The average mass (in grams) of a sample of rocks collected in the waters of a region.
Correct!
R

Question 11 1 I 1 ts
Suppose you want to measure the average level of education
in the population. You conduct a survey of people that live
nearby, and nd that your sample average is much higher
than you expected. What is most likely the cause?
Inaccurate

Question 10 1 / 1 ts
Note that for a random sample from an innite population,
the sample size times the sample proportion (n times p)
follows a binomial distribution. What distribution would n
times p follow if the population were nite?
Hint: Recall chapt

ECO 250-05
Name:
Spring 2017
Homework 4
_
10 points
Instructions: Legibly answer the following questions on separate sheets of paper. You must
show your work to get full credit for each problem.
1. (1.5 pt.) Consider the standard normal di

Question 9 1 l 1 Pts
What is the probability that x is less than 5.92?
0.9750 \
0.975 (with margin: 0.005)
Question 10 1 l 1 pts
What is the probability that x is between -1.92 and 5.92?
0.9500 \
0.95 cfw_with margin: 0.01)
Correct Answers
C

Question 10 1 I 1 Pts
Suppose that dataset A is a sample from an unknown
population. Also suppose that the sample mean has been
inuenced by an outlier. Calculate the sample standard
deviation if the outlier is excluded.
4.033 (with margin: 0.1)
Question 1

Question 8 1 I 1 Pts
Among the following, which is the most accurate statement
of the Central Limit Theorem?
Sample means are normally distributed.
Sample means are approximately normally
distributed.
if the sample size is large, the sample mean will be
c

Question 12 1 I 1 Pts
Calculate the median of dataset B.
11.0000
11.0 (with margin: 0.0)
What is the mode of dataset B?
Correct Answers
The mode is 20.
There is no mode in this dataset.
CDITECH i The modes are 8, 15, and 20.

Question 21 1 l 1 Pts
What is the probability that event B does not happen given
that event A happens?
Correct Answers
0.6 (with margin: 0.0)
What is the probability that either event A does not happen
or event B does happen?
You Answered
Correc

Data: values assigned to observations or measurements
Information: data that are transformed into useful facts that can be used for specific purpose,
such as making decisions
Data: raw facts or measurements of interest
Each value is considered a data poi

Homework business statistics
1. Which of the following is an example of discrete data?
The number of customers a restaurant serves each day in a given week.
The temperature taken at noon on every day during the month of January.
The times for a set of

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Practice1
A random sample of 60 teenagers revealed that teenagers received an average 2,272 text messages per month.
Using this sample, what is the standard error of the mean assuming the population standard deviation is 953 text
messages per month?
123.0

Question 1
C
Question 2
0
Question 3
1
Question 4
0.9406
P ( Z 1.56 ) =0.9406[ standard normal table ]
Question 5
0.648
P ( Z >0.38 )=0.648 [ standard normal table]
Question 6
0.7047
zscore=
x 140126
=
=0.538
26
P ( Z 0.538 ) =0.7047[ standard normal tabl