1. Mang Pedro uses the kaing to assess his harvest of mangoes. After he has
used a certain kind of fertilizer, the mangoes yield the following per kaing.
100 92 110 112 90 98 97 106 100 100
90 98 120 108 96 92 95 98 92 102
88 102 98 88 89 90 102 100 100 97
102 100 100 86 87 100 105 97 93 96
89 98 96 96 92 100 98 98 92 100
Consider each kaing (a group) a random sample. From past harvests, the
population standard deviation was observed to be 8 mangoes. Find the point and
the interval estimates of the population mean per kaing, using 98% confidence.
Step 1: The parameter of interest is the mean of the population where the
sample comes from.
Step 2: The sample information consists of raw scores = _____, and = _____.
The sample size of 50 kaing is large enough for the Central Limit Theorem
to satisfy the assumption that the sampling distribution of means is
normally distributed. The -test is also applicable.
Step 3: The level of confidence is _____ or = _____.
Critical values: _____.
This means that if more random samples are taken from the target
population and an interval estimate is made for each sample, then 95%
of the intervals ill contain the true parameter value.
Step 4: ̅ =
__+__+__+⋯+__
__
= ___ ≈ ___ mangoes
(the sample mean)
The point estimate is 98.
Step 5: = /2 (
√
)
= ___ (
___
√___
)
= _____
Interval estimate
̅ − /2 (
√
) < < ̅ + /2 (
√
)
̅ − _____ (
___
√___
) < < ̅ + _____ (
___
√___
)
_____ − _____ to _____ + _____
_____ to _____ or _____ to _____
Step 6: Result
We can say that __________________________________
_______________________________________________.