A junior high principal runs a report to determine what ratio of all 100 students take the bus to school or are dropped off by p
arents, based on grade (seventh grade or eight grade). The results are shown in the following probability distribution table.
Grade vs.
Transportation Takes
Bus Parents
Drop off Total
Seventh Grader 0.44 0.12 0.56
Eighth Grader 0.11 0.33 0.44
Total 0.55 0.45 1
What is the probability that a student is in seventh grade, given that he/she is dropped off by parents?
0.27
0.38
0.22
0.73
Grade vs.
Transportation Takes
Bus Parents
Drop off Total
Seventh Grader 0.44 0.12 0.56
Eighth Grader 0.11 0.33 0.44
Total 0.55 0.45 1
What is the probability that a student is in seventh grade, given that he/she is dropped off by parents?
0.27
0.38
0.22
0.73
2 answers:
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Answer:
2.28% probability that a person selected at random will have an IQ of 110 or greater
Step-by-step explanation:
Problems of normally distributed samples are solved using the z-score formula.
In a set with mean and standard deviation
, the zscore of a measure X is given by:
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
In this problem, we have that:
What is the probability that a person selected at random will have an IQ of 110 or greater?
This is 1 subtracted by the pvalue of Z when X = 110. So
has a pvalue of 0.9772
1 - 0.9772 = 0.0228
2.28% probability that a person selected at random will have an IQ of 110 or greater