The grade point averages for 10 randomly selected junior college students are listed below.
Assume the grade
point averages are normally distributed. Find a 98 confidence interval for the true mean. Round to the nearest
hundredth.
2.0 3.2 1.8 2.9 0.9 4.0 3.3 2.9 3.6 0.8
A) (1.55, 3.53 ) B) (0.67, 1.81 ) C) (2.12, 3.14 ) D) (3.11, 4.35 )
Q. 2The policy committee at State University has 6 members: John, Prof. Rise, Dr. Hernandez, LaToyna, Ming, and Jose. A subcommittee of two members must be formed to investigate the visitation policy in the dormitories.
List all possible simple random samples of size 2. A) John and Prof. Rise, John and Dr. Hernandez, John and LaToyna, John and Ming, John and Jose, Prof. Rise
and Dr. Hernandez, Prof. Rise and LaToyna, Prof. Rise and Ming, Prof. Rise and Jose, Dr. Hernandez and
LaToyna, Dr. Hernandez and Ming, Dr. Hernandez and Jose, LaToyna and Ming, LaToyna and Jose,
Ming and Jose
B) John and Prof. Rise, Dr. Hernandez and LaToyna, Ming and Jose
C) John and Prof. Rise, Prof. Rise and Dr. Hernandez, Dr. Hernandez and LaToyna, LaToyna and Ming,
Ming and Jose
D) John and Prof. Rise, John and Dr. Hernandez, John and LaToyna, John and Ming, John and Jose
Q. 3A new phone system was installed last year to help reduce the expense of personal calls that were being made by employees.
Before the new system was installed, the amount being spent on personal calls followed a normal distribution with an average of 500 per month and a standard deviation of 50 per month. Refer to such expenses as PCE's (personal call expenses). Using the distribution above, what is the probability that a randomly selected month had a PCE of between 375.00 and 590.00? A) 0.9579 B) 0.0421 C) 0.9999 D) 0.0001
Q. 4A random sample of 10 parking meters in a resort community showed the following incomes for a day.
Assume the incomes are normally distributed. Find the 95 confidence interval for the true mean. Round to
the nearest cent.
3.60 4.50 2.80 6.30 2.60 5.20 6.75 4.25 8.00 3.00
A) (3.39, 6.01 ) B) (2.11, 5.34 ) C) (4.81, 6.31 ) D) (1.35, 2.85 )
Q. 5The city council of a small town needs to determine if the town's residents will support the building of a new library. The council decides to conduct a survey of a sample of the town's residents.
Which one of the following procedures would be most appropriate for obtaining a sample of the town's residents? A) Survey a random sample of persons within each neighborhood of the town.
B) Survey a random sample of librarians who live in the town.
C) Survey 200 individuals who are randomly selected from a list of all people living in the state in which the
town is located.
D) Survey every 14th person who enters the old library on a given day.
Q. 6The number of violent crimes committed in a day possesses a distribution with a mean of 1.5 crimes per day and a standard deviation of four crimes per day.
A random sample of 140 days was observed, and the sample mean number of crimes for the sample was calculated. The data that was collected in this experiment could be measured with a __________ random variable. A) discrete B) continuous
Q. 7The amount of soda a dispensing machine pours into a 12 ounce can of soda follows a normal distribution with a mean of 12.39 ounces and a standard deviation of 0.26 ounce.
The cans only hold 12.65 ounces of soda. Every
can that has more than 12.65 ounces of soda poured into it causes a spill and the can needs to go through a
special cleaning process before it can be sold. What is the probability a randomly selected can will need to go
through this process?
A) 0.1587 B) 0.3413 C) 0.8413 D) 0.6587
Q. 8A study was designed to investigate the effects of two variables - (1 ) a student's level of mathematical anxiety and (2 ) teaching method - on a student's achievement in a mathematics course.
Students who had a low level of mathematical anxiety were taught using the traditional expository method. These students obtained a mean score of 290 with a standard deviation of 50 on a standardized test. Assuming no information concerning the shape of the distribution is known, what percentage of the students scored between 190 and 390? A) at least 75 B) approximately 95
C) at least 88.9 D) approximately 68
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