Algebra 1 Common Core Student Edition, Grade 8-9

a Lesso n Ch eck^

Do y o u k n o w H OW?

Find the mean, median, and mode of each data set.

Explain which measure best describes the data.

1.1 29 33 31 30 33 2. 8.2 9.3 8.5 8.8 9.0

3. A student has gotten the following grades on his tests:
   87, 95, 86, and 88. He needs to have an average of 90
   to receive an A for the class. What is the minimum
   grade he must get on the last test in order to have an
   average of 90?

____ ______ MATHEMATICAL

Do y o u UN DERSTAND? Jj g J PRA CTICES

4. Vocabulary How do mean, median, and mode
   describe the central tendency of a data set? Why are
   three different measures needed?


5. Erro r Analysis One student said 10 was the range of
   the data set 2,10, 8, and 3. Another student said the
   range was 8. Which student is correct? Explain.


6. Re a so n i n g How is the range of a data set affected by
   an outlier?

Pr act i ce an d Pr o b l em - So l v i n g Ex er ci ses

,1 ^ 1 Pr a c t i c e

MATHEMATICAL

PRA CTICES

Find the mean, median, and mode of each data set. Tell which measure of

central tendency best describes the data.

7. weights of books (oz): 12 10 9 15 16 10


8. golf scores: 98 96 98 134 99


9. time spent on Internet (min/day): 75 38 43 120 65 48 52


10. ages of students on math team: 14 14 15 15 16 15 15 16

Find the value of x such that the data set has the given mean.

11. 3.8, 4.2, 5.3, x; mean 4.8 12. 99, 86, 76, 95, x; mean 91


12. 100,121,105,113,108, x; mean 112 14. 31.7, 42.8, 26.4, x; mean 35

Se e Pr o b l e m 1.

4b See Problem 2.

15. Sales The line plot at the right shows the numbers of weekly
    sales a salesperson made in the first nine weeks of a ten-week sales
    period. The salesperson's target is an average of 14 sales each week.
    How many sales does the salesperson need in the tenth week to meet
    the target average?

Find the range and mean of each data set. Use your results to com pare the

two data sets.

Number of Weekly Sales

X X

XXX

X X X X

12 13 14 15

4/b See Problem 3.

16. Set A: 0 12 7 19 21
    Set B: 13 16 15 17 12
    17. Set C: 4.5 7.1 8.3 6.9
    Set D: 2.1 29.5 1.2 3.3
    18. SetE:113 183 479 120 117
    S etF :145 129 153 135 142


17. Sport s Over the past 6 seasons, one baseball player's batting averages were .265,
    .327, .294, .316, .281, and .318. A second player's batting averages were .304, .285,
    .312, .291, .303, and .314. What are the range and mean of each player’s batting
    averages? Use your results to compare the players’ batting skills.

742 Ch ap t er 12 Data Analysis and Probability