Question

1. a group of 21 students recorded how many hours they spent on homework last week. they created the dot plot below. dot plot of homework hours hours of homework a new student joins the group. he reports he spent 0 hours on homework and is added to the dot plot above. how will this new point affect the mean number of hours?

Explanation:

Step1: Count original data points

Check dot plot: 0h=0, 1h=5, 2h=7, 3h=5, 4h=3, 5h=1 → Total=5+7+5+3+1=21 (matches given)

Step2: Calculate original total hours

Total = (1×5)+(2×7)+(3×5)+(4×3)+(5×1) = 5+14+15+12+5=51

Step3: Calculate original mean

Mean = 51/21 ≈2.4286

Step4: Add new data point (0h)

New total hours=51+0=51; New count=22

Step5: Calculate new mean

New mean=51/22≈2.3182

Step6: Compare means

2.3182 < 2.4286 → Mean decreases

Answer:

The mean number of hours will decrease.