123

Chapter 12









Section 12.3

Exercise #1

Find the mean, median,

mode and midrange.

These data are the number of

burglaries reported in 1996 for nine

Western Pennsylvania universities.

61 11 1 3 2 30 18 3 7









Source: Pittsburgh Post Gazette

These data are the number of

burglaries reported in 1996 for nine

Western Pennsylvania universities.

1 2 3 3 7 11 18 30 61

X

mean = X = n

1 + 2 + 3 + 3 + 7 + 11 + 18 + 30 + 61

=

9

136

= = 15.11

9

 burglaries were reported per

15.11

university in W. Pennsylvania in 1996.

Source: Pittsburgh Post Gazette

These data are the number of

burglaries reported in 1996 for nine

Western Pennsylvania universities.

1 2 3 3 7 11 18 30 61

median:

(9 + 1)/2 = 5th value









Source: Pittsburgh Post Gazette

These data are the number of

burglaries reported in 1996 for nine

Western Pennsylvania universities.

1 2 3 3 7 11 18 30 61

median:

(9 + 1)/2 = 5th value



The median number of

reported burglaries of these

9 universities in 1996 was 7.



Source: Pittsburgh Post Gazette

These data are the number of

burglaries reported in 1996 for nine

Western Pennsylvania universities.

1 2 3 3 7 11 18 30 61

mode:









Source: Pittsburgh Post Gazette

These data are the number of

burglaries reported in 1996 for nine

Western Pennsylvania universities.

1 2 33 7 11 18 30 61

mode:



The mode of the number of

reported burglaries for these

universities in 1996 was 3.





Source: Pittsburgh Post Gazette

These data are the number of

burglaries reported in 1996 for nine

Western Pennsylvania universities.

1 2 3 3 7 11 18 30 61

midrange:

(L + H) (1 + 61) 62

= = = = 31

2 2 2

The midrange of the number of

burglaries of these W. Pennsylvania

universities in 1996 was 31.

Source: Pittsburgh Post Gazette

Chapter 12









Section 12.3

Exercise #7

Find the mean, median,

mode and midrange.

The number of hospitals for the 5

largest hospital systems is shown

here.

340 75 123 259 151









Source: USA Today

The number of hospitals for the 5

largest hospital systems is shown

here.

75 123 151 259 340

X

mean = X = n

75 + 123 + 151 + 259 + 340

=

5

948

= = 189.6

5

 is a mean of 189.6 hospitals

There

in the five largest hospital systems.

Source: USA Today

The number of hospitals for the 5

largest hospital systems is shown

here.

75 123 151 259 340

median:

(5 + 1)/2 = 3rd value









Source: USA Today

The number of hospitals for the 5

largest hospital systems is shown

here.

75 123 151 259 340

median:

(5 + 1)/2 = 3rd value



The median number of hospitals

in the 5 largest systems is 151.



Source: USA Today

The number of hospitals for the 5

largest hospital systems is shown

here.

75 123 151 259 340

mode:



There is no mode.









Source: USA Today

The number of hospitals for the 5

largest hospital systems is shown

here.

75 123 151 259 340

midrange:

(L + H) (75 + 340) 415

= = = = 207.5

2 2 2

The midrange of the number of

hospitals in the 5 largest hospital

systems is 207.5.

Source: USA Today

Chapter 12









Section 12.3

Exercise #11

Find the mean of the

grouped data.

For 50 antique car owner’s, the

distribution of the cars’ ages was

obtained as shown.

Class Frequency Midpoint

1618 20 (16+18)/2 = 17

1921 18 (19+21)/2 = 20

2224 8 (22+24)/2 = 23

2527 4 (25+27)/2 = 26

For 50 antique car owner’s, the

distribution of the cars’ ages was

obtained as shown.

Class Frequency Midpoint

1618 20 17

1921 18 20

2224 8 23

2527 4 26

50

For 50 antique car owner’s, the

distribution of the cars’ ages was

obtained as shown.

Class Frequency Midpoint

1618 20 17

1921 18 20

2224 8 23

2527 4 26

50

For 50 antique car owner’s, the

distribution of the cars’ ages was

obtained as shown.

Class Frequency Midpoint

1618 20 17

1921 18 20

2224 8 23

2527 4 26

50

For 50 antique car owner’s, the

distribution of the cars’ ages was

obtained as shown.

Class Frequency Midpoint

1618 20 17

1921 18 20

2224 8 23

2527 4 26

50

For 50 antique car owner’s, the

distribution of the cars’ ages was

obtained as shown.

Class Frequency Midpoint Midpoint x Freq

1618 20 17 (20)(17) = 340

1921 18 20 (18)(20) = 360

2224 8 23 (8)(23) = 184

2527 4 26 (4)(26) = 104

50

For 50 antique car owner’s, the

distribution of the cars’ ages was

obtained as shown.

Class Frequency Midpoint Midpoint x Freq

1618 20 17 340

1921 18 20 360

2224 8 23 184

2527 4 26 104

50 988



 f  X m 988

mean = X = n = = 19.76

50

For 50 antique car owner’s, the

distribution of the cars’ ages was

obtained as shown.

Class Frequency Midpoint Midpoint x Freq

1618 20 17 340

1921 18 20 360

2224 8 23 184

2527 4 26 104

50 988



The mean age of the antique cars is

approximately 19.76 years.