Answer :
How many standard deviations from the mean would a car going under the speed limit be -1.0787
Which would be more unusual: a car traveling 10 mph
Given data:
At speed limit of 20 mph mean of 100 readings was 23.84 mph
and a standard deviation of 3.56 mph
The speed limit read 20 mph
How to find the standard deviations from the mean that the car going under the speed limit
Assuming the car going under the speed limit of 20 mph be y
such that
20 = 23.84 + y * 356
356y = 20 - 23.84
y = ( 20 - 23.84 ) / 356
y = -1.0787
How to find which is more unusual
A car traveling 34 mph: using y same as number of deviations from the mean
34 = 23.84 + 3.56y
y = ( 34 - 23.84 ) / 3.56
y = 2.8539
Meaning the car travelling at 34 mph is 2.8539 standard deviations above the mean
A car traveling 10 mph: using y same as number of deviations from the mean
10 = 23.84 + 3.56y
y = ( 10 - 23.84 ) / 3.56
y = -3.8876
Meaning the car travelling at 10 mph is 3.8876 standard deviations below the mean
From the the rule that 99.7% of the observations lie with in ±3 standard. The speed of 10 mph is outside these limits but 34 mph is within the limits. Hence we say that the car travelling 10 mph is more unusual
Read more on standard deviation here: https://brainly.com/question/12402189
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