Chp 2
Chp 2
Chp 2
Chp 2
100
Many Professional schools require applicants to take a standardized test. Suppose that 1000 students take such a test. Several weeks after the test, Pete receives his score report; he got a 63 which placed him at the 73rd percentile. This means that...
73% of the test takers scored better than Pete
73% of the test takers scored the same as or lower than Pete
Pete did worse than about 73% of the test takers
73% of the test takers scored the same as or lower than Pete
100
The Environmental Protection Agency (EPA) requires that the exhaust of each model of motor vehicle be tested for the level of several pollutants. The level of oxides of nitrogen (NOX) in the exhaust of one light truck model was found to vary among individual trucks according to an approximately Normal distribution with a mean of 1.45 grams per mile driven and standard deviation of 0.40 grams per mile. Which of the following best estimates the proportion of light trucks of this model with NOX levels greater than 2 grams per mile?
0.04256
0.9154
0.0846
0.0846
100
As part of a student project, high school students were asked to sprint 50 yards and their times (in seconds) were recorded. A cumulative relative frequency graph of the sprint times is shown. One student ran the 50 yards in 8.05 seconds .
Is a sprint time of 8.05 seconds unusually slow?
No, a sprint time of 8.05 seconds is not unusually slow. A student with an 8.05 second sprint is at the 75th percentile, so 25% of students took longer than that.
100
A member of a track team was practicing the long jump and recorded the distance (in centimeters) shown in the dotplot. Some numerical summaries of the data are also provided. After chatting with a teammate, the jumper realized that he measured his jumps from the back of the board instead of the front. Thus, he had to subtract 20 centimeters from each of his jumps to get the correct measurement for each jump.
What shape would the distribution of the corrected long jump distance have?
The shape of the corrected long jump distance will be roughly symmetric with a single peak.
200
Rainwater was collected in water containers at 30 different sites near an industrial complex, and the amount of acidity (pH level) was measured. The mean and standard deviation of the values are 4.60 and 1.10 respectively. When the pH meter was recalibrated back at the laboratory, it was found to be in error. The error can be corrected by adding 0.1 pH unit to all of the values and then multiplying the results by 1.2.
What are the mean and standard deviation of the correct pH measurements?
5.64, 1.32
200
A member of a track team was practicing the long jump and recorded the distance (in centimeters) shown in the dotplot. Some numerical summaries of the data are also provided. After chatting with a teammate, the jumper realized that he measured his jumps from the back of the board instead of the front. Thus, he had to subtract 20 centimeters from each of his jumps to get the correct measurement for each jump.
What are the mean and median of the distribution of the corrected long jump distance?
Mean=557.3cm
Median=557cm
200
The weights of laboratory cockroaches can be modeled with a normal distribution having mean 80 grams and standard deviation 2 grams. The following figure is the Normal curve for this distribution of weights.
About what percent of the cockroaches have weights between 76 and 84 grams?
95%
200
The deciles of any distribution are the values at the 10th, 20th,...90th percentiles.Thus the first decile is the 10th percentile.
What is the first decile of the standard normal distribution?
-1.28
300
Which of the following statements is true?
The area under the curve between A and G is 1
The mean of the distribution is E
The median of the Distribution is C
The area under the curve between A and G is 1
300
A member of a track team was practicing the long jump and recorded the distance (in centimeters) shown in the dotplot. Some numerical summaries of the data are also provided. After chatting with a teammate, the jumper realized that he measured his jumps from the back of the board instead of the front. Thus, he had to subtract 20 centimeters from each of his jumps to get the correct measurement for each jump.
What is the standard deviation and interquartile range (IQR) of the distribution of corrected long jump distances?
SD=4.713cm
IQR=7cm
300
Mrs. Starnes enjoys doing Sudoku puzzles. The time she takes to complete an easy puzzle can be modeled by a Normal distribution with mean 5.3 minutes and Standard deviation 0.9 minutes.
21.8%
300
The following figure is a normal probability plot of the heart rates of 200 male runners after 6 minutes of exercise on a treadmill.
What is the shape of the distribution of heart rates?
Approximately Normal
400
If the heights of a population of men are approximately Normally distributed, and the middle 99.7% have heights between 5'0 and 7'0, what is the standard deviation of the heights in this population?
4"
400
How many pairs of shoes does a typical teenage boy own? To find out, two AP statistics students surveyed a random sample of 20 male students from their large high school. Then they recorded the number of pairs of shoes that each boy owned. Given is a dot plot of the data. One of the students, Jackson, reported owning 22 pairs of shoes.
What is Jackson's percentile?
90th Percentile
400
Two measures of center are marked on the density curve shown.
Which of the following is correct?
The mean is at the red line and the median is at the yellow line
The median is at the red line and the mean is at the yellow line
The mode is at the red line and the median is at the yellow line
The median is at the red line and the mean is at the yellow line
400
Given is a stemplot of the percents of residents aged 65 and older in the 50 states:
What is the percentile for Colorado, where 10.1% of the residents are aged 65 and older?
10th percentile