Do the experiment results match the math?

Answer Key - Grade 7 Math Worksheet

Circle the best answer, or write your answer on the line.

1. 1.

   Ari flips a water bottle 40 times and it lands upright 14 times. Using these results as the model, how many uprights should Ari expect in 200 more flips?

   70
2. 2.

   Esme plants 60 bean seeds and 27 sprout. Using that as the model, how many sprouts should Esme expect from 400 seeds?

   180
3. 3.

   The bus Jun rides was late on 6 of 25 mornings. Using that as the model, on about how many of 500 mornings should Jun expect the bus to be late?

   120
4. 4.

   Jun's spinner has 4 equal sections, so gold has a 1/4 chance. Jun gets gold 14 times in 40 spins. Zee gets gold 108 times in 400 spins. Whose result is closer to the model?

   • Jun's result: the tally is 4 above the expected 10, while Zee's is 8 above the expected 100.
   • Neither is closer, since both tallies are above the expected count for their spins.
   • Zee's result: 27% is 2 points from 25%, while Jun's 35% is 10 points away.
5. 5.

   A fair coin has a 1/2 chance of heads. Ari gets 9 heads in 20 flips. Ren gets 90 heads in 200 flips. Whose result is closer to the model?

   • They are equally close: both shares are 45%, which is 5 points under 50%.
   • Ren's result: 200 flips is a larger sample, so it has to be closer to the model.
   • Ari's result: 9 is 1 under the expected 10, while Ren's 90 is 10 under the expected 100.
6. 6.

   Luz's spinner has 5 equal sections, 3 of them green, a 0.6 chance. Luz lands on green 19 times in 30 spins. Tala lands on green 135 times in 200 spins. Whose result is closer?

   • Tala's result: 200 spins is a larger sample than 30 spins, so Tala's has to be closer.
   • They are equally close, since both shares are above the 60% that the model gives.
   • Luz's result: 19/30 is about 63%, 3 points over 60%, while Tala's 67.5% is 7.5 over.
7. 7.

   Kira's spinner has 10 equal sections, 3 of them gold, a 0.3 chance. Kira gets gold 21 times in 60 spins. Pia gets gold 93 times in 300 spins. Whose result is closer?

   • Pia's result: 93/300 is 31%, 1 point over 30%, while Kira's 35% is 5 points over.
   • Kira's result: the tally is 3 above the expected 18, while Pia's is 3 above the expected 90.
   • They are equally close, since both tallies miss the expected count by 3.
8. 8.

   Tala's spinner has red, blue and green. In 120 spins, red came up 61 times, blue 30 and green 29. Which model of the spinner is most reasonable?

   • Red 1/3, blue 1/3, green 1/3, because a spinner with three colors gives each one a 1/3 chance.
   • Red 1/6, blue 1/3, green 1/2, because the color with the smallest tally should get the biggest chance.
   • Red 1/2, blue 1/4, green 1/4, because the tallies sit near 60, 30 and 30.
   • Red 2/3, blue 1/6, green 1/6, because red came up more times than blue and green put together.
9. 9.

   Noah rolls a number cube 60 times. The counts for faces 1 to 6 are 8, 9, 11, 10, 12 and 10. A fair cube gives about 10 of each. What can Noah say?

   • Only the 4 and the 6 came up exactly 10 times, so the cube seems unfair.
   • Every count is within 2 of 10, so the fair-cube model seems reasonable.
   • The six counts add up to 60 rolls, so the fair model is right.
   • The 5 came up most, so a 5 has the biggest chance and the model should say so.
10. 10.

    A game spinner is designed with red 1/2, blue 1/3 and green 1/6. In 120 spins, Pia gets red 52, blue 46 and green 22. Which statement fits best?

    • The tallies miss 60, 40 and 20 by 8, 6 and 2, so the three chances in the design are wrong.
    • The tallies add up to 120 spins, so the total is what matters and the design is right.
    • The tallies are within 8 of the expected 60, 40 and 20, so the design seems reasonable.
    • Blue came up more than green, so green should have the bigger chance of the two.