Answer:
or
Step-by-step explanation:
Scott received scores of 91, 85, and 89 on three tests. What score must Scott get on the fourth test to have an overall average
1 answer:
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Answer:
Percentile 5
And if we solve for a we got
Percentile 95
And if we solve for a we got
Step-by-step explanation:
Let X the random variable that represent the variable of interest of a population, and for this case we know the distribution for X is given by:
Where and
We want to find the percentiles 5 and 95 for this case.
Percentile 5
For this part we want to find a value a, such that we satisfy this condition:
(a)
(b)
We want to find a percentile with 0.95 of the area on the left and 0.05 of the area on the right it's z=-1.64. On this case P(Z<-1.64)=0.05 and P(z>-1.64)=0.05
Using this condition we got:
Replacing we got:
And if we solve for a we got
Percentile 95
And if we solve for a we got