Statistics in a Modern World 800
Homework 3 NAME:_________________________________

Homework 3 Exercises Assigned from Chapters 7-8 (21 pts.) due Fri., September 27 in Lecture.

CHAPTER 7

#1 (4 pts.) At the beginning of this chapter, the following exam scores were listed: 75, 95, 60, 93, 85, 84, 76, 92, 62, 83, 80, 90, 64, 75, 79, 32, 78, 64, 98, 73, 88, 61, 82, 68, 79, 78, 80, 55.

  1. At the bottom left of this page, create a stemplot for the test scores.
  2. The shape as shown by the stemplot is (i) symmetric (ii) skewed right/high outlier(s) (iii) skewed left/low outlier(s)
  3. The shape is (i) unimodal (ii) bimodal
  4. Are there any outliers? If so, tell what they are.

#2. (2 pts.) Refer to the test scores in Exercise 1.

  1. List the values of the Five Number Summary, from lowest to highest.
  2. At the bottom middle of this page, create a boxplot.

#3 (1 pt.) At the bottom right of this page, create a histogram for the test scores.

#8 (2 pts.) Find the mean and standard deviation of these numbers: 10, 20, 25, 30, 40.

#12 (2 pts.) In each of the following cases, which would probably be higher, the mean or the median, or would they be about equal?

  1. Salaries in a company employing 100 factory workers and 2 highly paid executives (i) mean higher (ii) median higher (iii) about equal
  2. Ages at which residents of a suburban city die, including everything from infant deaths to the most elderly (i) mean higher (ii) median higher (iii) about equal
  3. Heights of all 7-year-old children in a large city (i) mean higher (ii) median higher (iii) about equal
  4. Shoe sizes of adult women (i) mean higher (ii) median higher (iii) about equal

 

 

 

 

 

 

 

 

 

CHAPTER 8

# 1 (1.5 pts.) Using Table 8.1 p.157 (handed out in class), determine the percentage of the population falling BELOW each of the following standard scores:

  1. -1.00
  2. 1.96
  3. 0.84

#2 (1.5 pts.) Using Table 8.1, determine the percentage of the population falling ABOVE each of the following standard scores:

  1. 1.28
  2. -0.25
  3. 2.33

#3 (2 pts.) Using Table 8.1, determine the standard score that has the following percentage of the population BELOW it:

  1. 25%
  2. 75%
  3. 45%
  4. 98%

#4 (2 pts.) Using Table 8.1, determine the standard score that has the following percentage of the population ABOVE it:

  1. 2%
  2. 50%
  3. 75%
  4. 10%

#5 (1 pt.) Using Table 8.1, determine the percentage of the population falling between the two standard scores given:

  1. -1.28 and 1.75
  2. 0.0 and 1.0

#9 (1 pt.) Stanford-Binet IQ's have mean 100, standard deviation 16. Mensa is an organization that allows people to join only if their IQ's are in the top 2% of the population. What is the lowest Stanford-Binet IQ you could have and still be eligible to join Mensa? Show your work.

 

 

 

 

 

#14 (1 pt.) A graduate school program in English will admit only students with GRE verbal ability scores in the top 30%. What is the lowest GRE score they will accept? (Recall the mean is 497 and the standard deviation is 115.) Show your work.

 

 

 

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