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Name: __________________________________________________________ Period: _________ Wednesday 10/22/14
A2H
Classwork
Unit 3 – Statistics
#1 - 2 Use the vocabulary words you just read about to answer the questions below.
1. Danny did a statistical study about the average number of hours American teenagers spend on Instagram. She
sampled 500 students at her high school using a random number generator. She found that the average number
of hours the students at her high school spend on Instagram is 3 hours a week; the national average is 5 hours
per week.
a. What is the population?
b. What is the sample?
c. What is the parameter?
d. What is the statistic?
e. What is the treatment?
2. Diana did a statistical study about the average height of kindergarteners in Colorado. She traveled to ten
different elementary schools including both rural and urban schools. She found that average height of the
kindergarteners in the elementary schools she visited was 38 inches.
a. What is the population?
b. What is the sample?
c. What is the statistic?
d. Can Diana apply the statistic to the population? Explain.
#3 – 4 Use the 68-95-99.7 rule to calculate the percentage of values under the area of the Normal curve.
3. The scores on the exam from AP Biology are posted. The mean is 75 and the standard deviation is 5. Use the
Normal curve below to help show your work.
a. James scored an 80. What percent of the students scored higher than James?
b. Mary scored an 85. What percent of the students scored higher than Mary?
c. Tom scored a 70. What percent of the students scored below Tom?
d. What percent of students scored between a 75 and an 85?
e. If 70 is passing, what percent of the students passed the exam?
#3 – 4 Use the 68-95-99.7 rule to calculate the percentage of values under the area of the Normal curve.
4. Women’s weights are Normally distributed with a mean of 143 lbs. and a standard deviation of 29 lbs.
a. Between what two weights do 68% of women fall?
b. What percent of women weight more than 201 pounds?
c. Between what two values are 99.7% of the values?
d. What percent of women weight between 114 and 143 pounds?
e. What percent of women weight between 143 and 201 pounds?
#5 – Use the 68-95-99.7 rule to estimate the percentage of values under the area of the Normal curve.
5. Women’s heights have a mean of 63.6” and a standard deviation of 2.5.
a. Draw the Normal curve described above in the space provided below.
b. Estimate the percentage of women whose heights fall between 60 and 64 inches.
c. Estimate the percentage of women whose heights fall between 57 and 69 inches.
d. Estimate the percentage of women whose heights fall between 62 and 65 inches.
ANSWERS
A2H
Classwork
Unit 3 – Statistics
#1 - 2 Use the vocabulary words you just read about to answer the questions below.
1. Danny did a statistical study about the average number of hours American teenagers spend on Instagram. She
sampled 500 students at her high school using a random number generator. She found that the average number
of hours the students at her high school spend on Instagram is 3 hours a week; the national average is 5 hours
per week.
a. What is the population? All American teenagers
b. What is the sample?
500 students at Danny’s high school
c. What is the parameter? 5 hours
d. What is the statistic?
3 hours
e. What is the treatment? Number of hours spent on Instagram
2. Diana did a statistical study about the average height of kindergarteners in Colorado. She traveled to ten
different elementary schools including both rural and urban schools. She found that average height of the
kindergarteners in the elementary schools she visited was 38 inches.
a. What is the population? All Kindergarteners in Colorado
b. What is the sample?
Kindergarteners at elementary schools visited by Diana in CO
c. What is the statistic?
38 inches
d. Can Diana apply the statistic to the population? Explain. No, the statistic only applies to the sample.
#3 – 4 Use the 68-95-99.7 rule to calculate the percentage of values under the area of the Normal curve.
3. The scores on the exam from AP Biology are posted. The mean is 75 and the standard deviation is 5. Use the
Normal curve below to help show your work.
a. James scored an 80. What percent of the students scored higher than James? 16%
b. Mary scored an 85. What percent of the students scored higher than Mary? 2.5%
c. Tom scored a 70. What percent of the students scored below Tom? 16%
d. What percent of students scored between a 75 and an 85? 47.5%
e. If 70 is passing, what percent of the students passed the exam? 84%
60
65
70
75
80
85
90
#3 – 4 Use the 68-95-99.7 rule to calculate the percentage of values under the area of the Normal curve.
4. Women’s weights are Normally distributed with a mean of 143 lbs. and a standard deviation of 29 lbs.
a. Between what two weights do 68% of women fall? 114 and 172
b. What percent of women weight more than 201 pounds? 2.5%
c. Between what two values are 99.7% of the values? 56 to 230
d. What percent of women weight between 85 and 114 pounds? 13.5%
e. What percent of women weight between 172 and 230 pounds? 15.85%
#5 – Use the 68-95-99.7 rule to estimate the percentage of values under the area of the Normal curve.
5. Women’s heights have a mean of 63.6” and a standard deviation of 2.5.
a. Draw the Normal curve described above in the space provided below.
b. Estimate the percentage of women whose heights fall between 60 and 64 inches. 49%
c. Estimate the percentage of women whose heights fall between 57 and 69 inches. 98%
56.1
58.6
61.1
63.6
66.1
68.6
71.1