What is the inverse of f(x) = x/5 -2
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Answer:
Test scores of 10.2 or lower are significantly low.
Test scores of 31.4 or higher are significantly high.
Step-by-step explanation:
Problems of normally distributed samples can be 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:
Identify the test scores that are significantly low or significantly high.
Significantly low
Z = -2 and lower.
So the significantly low scores are thoses values that are lower or equal than X when Z = -2. So
Test scores of 10.2 or lower are significantly low.
Significantly high
Z = 2 and higher.
So the significantly high scores are thoses values that are higherr or equal than X when Z = 2. So
Test scores of 31.4 or higher are significantly high.
There are 400 balcony seats in the concert hall.
<u>Step-by-step explanation</u>:
Step 1 :
- The number of lower seats = 450 seats
Total seats = Lower seats + balcony seats
Step 2 :
- Tickets sold = 170 tickets
- Total tickets = x
Tickets sold = 1/5 of total tickets.
⇒ 170 = (1/5)x
⇒ x = 5170
⇒ x = 850 tickets
∴ Total seats in the concert hall is 850.
Step 3 :
Total seats = 450 + balcony seats
850 - 450 = balcony seats
∴ balcony seats = 400