7th Grade Data and Statistics

Juanita surveyed a random sample of 20 students in the school band as to how many hours per week they practiced at home. The results are shown in the table below. Which of the following is a reasonable conclusion based on the mean number of hours per week the boys and girls each spent practicing.

• The girls generally practice slightly more than the boys.

• The girls generally practice much more than the boys.

• The boys generally practice slightly more than the girls.

• The boys generally practice much more than the girls.

Nadia is conducting an experiment where she repeatedly draws a marble from a bag without looking, records its color, and replaces it. She conducted 40 trials in the experiment, with the results shown below. If Nadia were to conduct the same experiment with 2,000 draws, approximately how many times could she expect to draw a yellow marble?

• 400

• 125

• 250

• 500

The school food service wants to increase the number of students who eat hot lunch in the cafeteria. The student council has been asked to conduct a survey of the student body to determine the students’ preferences for hot lunch. Which survey option should the student council use?

• Write all of the students’ names on cards and pull them out in a draw to determine who will complete the survey.

• Survey the first 20 students that enter the lunchroom.

• Survey every 3rd student who gets off a bus.

If Mary chooses a point in the square, what is the probability it is not in the circle? Express your answer as a decimal.

(a)  

Jason is tossing a fair coin. He tosses the coin ten times and it lands on heads eight times. If Jason tosses the coin an eleventh time, what is the probability that it will land on heads?

(a)  

About how many times should you expect to roll an even number on a standard 1-6 number cube if you roll it 600 times?

(a)  

Cedric has 1 red pen, 1 blue pen, and 1 black pen in his desk. If he randomly draws two of them from the desk without replacement, what is the probability he will draw the blue and black pens?

Enter answer as a fraction.

(a)  

The probability of an event is 1. Which word best describes this probability?

• impossible

• unlikely

• equally likely

• likely

• certain

A fair coin will be tossed three times. What is the probability that two heads and one tail in any order will result?

• 1/2

• 1/3

• 1/6

• 1/8

Abdul surveyed a random sample of adults to find out how many hours per night they sleep. The results are shown below.

7,7,6,8,8,7,7,8,6,7,5,8,8,7,6,7,6,9,6,7

What is the mean number of hours of sleep for the population from which the sample was drawn?

(a)