7th Grade Math

EP24 Extra Practice

Extra Practice

Multi-Part Lesson 8-3 (continued)

PART F PAGES 472–476

Determine whether the conclusions are valid. Justify your answer.

1. To award prizes at a hockey game, four tickets with individual seat
   numbers printed on them are picked from a barrel. Since Elvio’s section
   was not selected for any of the four prizes, he assumes that they forgot to
   include the entire section in the drawing.


2. To evaluate the quality of the televisions coming off the assembly line,
   the manufacturer takes one every half hour and tests it. About 1 out of
   every 10,000 is found to have a minor mechanical problem. The company
   assumes from this data that about 1 out of every 10,000 televisions they
   produce will be returned for mechanical problems after being purchased.


3. To determine whether most students participate in after school activities,
   the principal of Humberson Middle School randomly surveyed 75 students
   from each grade level. Of these, 34% said they participate in after school
   activities. The principal concluded that about a third of the students at
   Humberson Middle School participate in after school activities.

Multi-Part Lesson 9-1: Measures of Central Tendency

PARTS A B C PAGES 490–497

Find the mean, median, and mode for each data set. Round to the nearest

tenth if necessary.

1. number of siblings: 2, 5, 8, 9, 7, 6, 3, 5, 1, 4


2. ages of children living on a street: 1, 5, 9, 1, 2, 6, 8, 2


3. points scored each game: 82, 79, 93, 91, 95, 95, 81


4. number of coins saved: 117, 103, 108, 120


5. E-mails sent this month: 256, 265, 247, 256


6. typing speed in words per minute: 47, 54, 66, 54, 46, 66

Multi-Part Lesson 9-2: Measures of Variation

PART A PAGES 498–503

Find the range, median, lower and upper quartiles, interquartile range, and

any outliers for each set of data.

1. ages of players on a team: 15, 12, 21, 18, 25, 11, 17, 19, 20


2. ages of cousins: 2, 24, 6, 13, 8, 6, 11, 4


3. dollars in an account: 189, 149, 155, 290, 141, 152


4. daily attendance at a fair: 451, 501, 388, 428, 510, 480, 390


5. number of calls made: 22, 18, 9, 26, 14, 15, 6, 19, 28


6. text messages recieved: 245, 218, 251, 255, 248, 241, 250


7. ages of people in a restaurant: 46, 45, 50, 40, 49, 42, 64


8. points earned in a game: 128, 148, 130, 142, 164, 120, 152, 202

EP2_EP36_ExtPract_M1_895130.indd EP24 1/6/10 11:46 AM