EXST 2201 EXAM QUESTIONS
WITH REVISED AND UPDATED
ANSWERS
The standard error gives the spread of the column of data values. - Answer-False
Is there a definite, specific relationship between the spread of the sample average and
the spread of the data? - Answer-Yes
The intelligent quotient (IQ) of a human adult can be measured with the stanford-binet
intelligence test where the test scores are standardized to a normal shape, a mean of
100, and a standard deviation of 16. If a score below 69 is used as evidence of mental
retardation, what is the chance that a group of 3 human adults would be classified as
mentally retarded based on their average IQ? - Answer-0.0004
The blood pressure human adults follows a normal distribution with mean 116
millimeters of mercury and standard deviation 9.6 millimeters of mercury. A random
sample of 18 human adults is measured and the average calculated. What is the
probability that the average blood pressure is between 110 and 122 millimeters of
mercury? - Answer-0.9920
What is the location of the t-Distribution? - Answer-The t-distribution has a mean of zero
What is the spread of the t-Distribution - Answer-the t-distribution has a different spread
for every degree of freedom
A town in Sweden was known to have long-lived residents with a mean life span of 80
years. To find out if this was still true, a sociology researcher looked at several samples
of 40 residents that had a standard deviation life span of 8 years. What would be the
lowest and the highest life span of the middle 90% these residents? - Answer-Between
79.2 years and 80.7 years
A restaurant chain has a known satisfaction rating of 8.6 units. A local restaurant owner
wants to know how his restaurant compares, so he asks 25 customers for their
satisfaction ratings and records the average rating. The sample standard deviation of
this sample was calculated to be 1.5 units. What average rating would the owner need
to have so that less than 25% of his customers disliked his restaurant? - Answer-The
owner would need an average rating of 8.39 units
A normal curve can be described with on specific mathematical equation, if the values
of the variable are known - Answer-True
, Which of the following answers is NOT true of a statistical event? - Answer-A event is
an area under a normal curve
If the area under a normal curve less than z=-1.75 quals 0.04, what is the area under
the curve between z=--1.75 and z=+1.75? - Answer-0.92
In the standard normal distribution, what are z-scores used to describe? - Answer-The
event on the x-axis
Use the schematic curve and the z-table to find the proportion of a population having a
z-score less than +0.44 - Answer-0.6700
Use the schematic curve and the z-table to find the z-score that separates the bottom
86% of the individuals from the top 14%? - Answer-z=+1.08
x-values have no units of measurement associated with them - Answer-False
For a city where the prices of new homes were distributed normally with a population
mean price of $150,000 and a population standard deviation price of $11,000, what
proportion of new homes are priced between $145,000 and $155,000 - Answer-0.3472
At a local secondary school, the school children were known to run a race with the race
times distributed normally with a population mean time of 450 seconds and a population
standard deviation time of 50 seconds. With this information, what is the shortest time
and the longest time of the middle third (34%) of the children? - Answer-428 seconds,
and 472 seconds
The sampling distribution of the sample average has the same shape, location, and
spread as does the data values? - Answer-False
What characteristic of the sampling distribution of the sample average is the Central
Limit Theorem concerned with? - Answer-Shape of the sample averages
The intelligent quotient (IQ) of a human adult can be measured with the stanford-binet
intelligence test where the test scores are standardized to a normal shape, a mean of
100, and a standard deviation of 16. A study done by Virginia Tech found that American
football players had an average IQ of 103. What is the chance that LSU's team of 11
players has an average IQ greater than 103? - Answer-26.76%
The score of golfers at a local golf course has an unknown distribution with a mean 79
and a standard deviation 3.5. A random sample of 49 golfers is measured and the
average calculated. What is the probability that the average score is greater than 80? -
Answer-0.0228
WITH REVISED AND UPDATED
ANSWERS
The standard error gives the spread of the column of data values. - Answer-False
Is there a definite, specific relationship between the spread of the sample average and
the spread of the data? - Answer-Yes
The intelligent quotient (IQ) of a human adult can be measured with the stanford-binet
intelligence test where the test scores are standardized to a normal shape, a mean of
100, and a standard deviation of 16. If a score below 69 is used as evidence of mental
retardation, what is the chance that a group of 3 human adults would be classified as
mentally retarded based on their average IQ? - Answer-0.0004
The blood pressure human adults follows a normal distribution with mean 116
millimeters of mercury and standard deviation 9.6 millimeters of mercury. A random
sample of 18 human adults is measured and the average calculated. What is the
probability that the average blood pressure is between 110 and 122 millimeters of
mercury? - Answer-0.9920
What is the location of the t-Distribution? - Answer-The t-distribution has a mean of zero
What is the spread of the t-Distribution - Answer-the t-distribution has a different spread
for every degree of freedom
A town in Sweden was known to have long-lived residents with a mean life span of 80
years. To find out if this was still true, a sociology researcher looked at several samples
of 40 residents that had a standard deviation life span of 8 years. What would be the
lowest and the highest life span of the middle 90% these residents? - Answer-Between
79.2 years and 80.7 years
A restaurant chain has a known satisfaction rating of 8.6 units. A local restaurant owner
wants to know how his restaurant compares, so he asks 25 customers for their
satisfaction ratings and records the average rating. The sample standard deviation of
this sample was calculated to be 1.5 units. What average rating would the owner need
to have so that less than 25% of his customers disliked his restaurant? - Answer-The
owner would need an average rating of 8.39 units
A normal curve can be described with on specific mathematical equation, if the values
of the variable are known - Answer-True
, Which of the following answers is NOT true of a statistical event? - Answer-A event is
an area under a normal curve
If the area under a normal curve less than z=-1.75 quals 0.04, what is the area under
the curve between z=--1.75 and z=+1.75? - Answer-0.92
In the standard normal distribution, what are z-scores used to describe? - Answer-The
event on the x-axis
Use the schematic curve and the z-table to find the proportion of a population having a
z-score less than +0.44 - Answer-0.6700
Use the schematic curve and the z-table to find the z-score that separates the bottom
86% of the individuals from the top 14%? - Answer-z=+1.08
x-values have no units of measurement associated with them - Answer-False
For a city where the prices of new homes were distributed normally with a population
mean price of $150,000 and a population standard deviation price of $11,000, what
proportion of new homes are priced between $145,000 and $155,000 - Answer-0.3472
At a local secondary school, the school children were known to run a race with the race
times distributed normally with a population mean time of 450 seconds and a population
standard deviation time of 50 seconds. With this information, what is the shortest time
and the longest time of the middle third (34%) of the children? - Answer-428 seconds,
and 472 seconds
The sampling distribution of the sample average has the same shape, location, and
spread as does the data values? - Answer-False
What characteristic of the sampling distribution of the sample average is the Central
Limit Theorem concerned with? - Answer-Shape of the sample averages
The intelligent quotient (IQ) of a human adult can be measured with the stanford-binet
intelligence test where the test scores are standardized to a normal shape, a mean of
100, and a standard deviation of 16. A study done by Virginia Tech found that American
football players had an average IQ of 103. What is the chance that LSU's team of 11
players has an average IQ greater than 103? - Answer-26.76%
The score of golfers at a local golf course has an unknown distribution with a mean 79
and a standard deviation 3.5. A random sample of 49 golfers is measured and the
average calculated. What is the probability that the average score is greater than 80? -
Answer-0.0228
