3.5 Sample Size
Section 3.5
Sample Size
How many samples
should you take?
Too many
wasted
money
Too few
inaccurate
conclusions
1
3.5 Sample Size
CHOOSING AN APPROPRIATE SAMPLE SIZE
DEPENDS ON 3 FACTOR
Time spent on the internet per week follows a normal distribution with an average 13.5
hours per week and a standard deviation of 5.6 hours.
a) Can we assume a normal distribution of sample means?
b)
Time spent on the internet per week follows a normal distribution with an average 13.5
hours per week and a standard deviation of 5.6 hours.
a) Can we assume a normal distribution of sample means?
b)
In a recent survey of 200 people who taste tested a new kind cereal, 46 people said they would purchase it.
The manufacturer thought it would be worth while launching the new cereal if more than 20% o
In a recent survey of 200 people who taste tested a new kind cereal, 46 people said they would purchase it.
The manufacturer thought it would be worth while launching the new cereal if more than 20% o
Historically at Jamestown Steel Co. daily production of desks follows a normal
distribution with a mean of 200 and standard deviation of 16. A new production
method was recently introduced, and the co
Historically at Jamestown Steel Co. daily production of desks follows a normal
distribution with a mean of 200 and standard deviation of 16. A new production
method was recently introduced, and the co
Historically at Jamestown Steel Co. daily production of desks follows a normal
distribution with a mean of 200 and standard deviation of 16. A new production
method was recently introduced, and the co
A recent article in a magazine reported that a job awaits only 1 in 3 new college
graduates across Canada. A random sample of 200 recent Fanshawe
graduates revealed that 80 had jobs. At the .02 signif
A recent article in a magazine reported that a job awaits only 1 in 3 new college
graduates across Canada. A random sample of 200 recent Fanshawe
graduates revealed that 80 had jobs. At the .02 signif
In order to estimate the mean amount spent by all costumers, a retail chain surveyed
400 random purchases. The sample showed a mean purchase amount of $500 and a
standard deviation of $100. Establish
In order to estimate the mean amount spent by all costumers, a retail chain surveyed
400 random purchases. The sample showed a mean purchase amount of $500 and a
standard deviation of $100. Establish
A Survey of 700 consumers shows that 500 purchase sugar-free gum regularly.
Contstruct a 95% confidence interval for the population proportion of customers who
regularly purchase sugar-free gum.
= 0.
A Survey of 700 consumers shows that 500 purchase sugar-free gum regularly.
Contstruct a 95% confidence interval for the population proportion of customers who
regularly purchase sugar-free gum.
=
p=(
A study is set up to determine the average remuneration earned by members of city council
in large cities. It is desired that the error from the mean is less than $5,000 with a 95% level
of confidence
A study is set up to determine the average remuneration earned by members of city council
in large cities. It is desired that the error from the mean is less than $5,000 with a 95% level
of confidence
1.1 Sampling Methods
Section 1.1
Sampling Methods
STATISTICS
1
1.1 Sampling Methods
TYPE OF STATISTICS
DESCRIPTIVE
INFERENTIAL
Methods of organizing,
summarizing, and
presenting data in an
informative
1.1 Sampling Methods
Section 1.1
Sampling Methods
STATISTICS
The science of collecting,
organizing, presenting,
analyzing, and interpreting data
to assist in making more
effective decisions
1
1.1 Samp
Consider a plant with a very large number of workers. The plant has a mean age
of 50 years, with a standard deviation of 4 years.
a) What is the z-score of a worker who is 57 years of age?
b) What per
Consider a plant with a very large number of workers. The plant has a mean
age of 50 years, with a standard deviation of 4 years.
a) What is the z-score of a worker who is 57 years of age?
b) What per
CONFIDENCE INTERVALS & SAMPLE SIZE
1.
2.
3.
4.
5.
6.
7.
8.
The owner of Brittens Egg Farm wants to estimate the mean number of eggs
laid per chicken. A sample of 20 chickens shows they laid an average
The following is a list of Tim Horton's Locations in London, Ontario. In order to gain
information on customer satisfaction with drive thru service, customers will be surveyed at 7
randomly selected l
The following is a list of Tim Horton's Locations in London, Ontario. In order to gain
information on customer satisfaction with drive thru service, customers will be surveyed at 7
randomly selected l
Create a HISTOGRAM for the following example:
The Wachesaw Outpatient Centre, designed for same-day minor surgery,
opened last month. Following is the number of patients served for the
first 10 days:
Create a HISTOGRAM for the following example:
The Wachesaw Outpatient Centre, designed for same-day minor surgery,
opened last month. Following is the number of patients served for the
first 10 days:
The following data is from a quality assurance check on filling levels of 591mL
bottles at Coca-Cola. Find the MEAN, MEDIAN, and MODE for the data.
591.33
591.68
590.53
590.87
590.75
590.31
590.73
591
The following data is from a quality assurance check on filling levels of 591mL
bottles at Coca-Cola. Find the MEAN, MEDIAN, and MODE for the data.
591.33
591.68
590.53
590.87
590.75
590.31
590.73
591
The following data is from a quality assurance check on filling levels of 591mL
bottles at Coca-Cola. Find the STANDARD DEVIATION, VARIANCE, and
INTERQUARTILE RANGE for the data.
591.33
591.68
590.53
The following data is from a quality assurance check on filling levels of 591mL
bottles at Coca-Cola. Find the STANDARD DEVIATION, VARIANCE, and
INTERQUARTILE RANGE for the data.
591.33
591.68
590.53