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(All D&V) Wednesday!
Two-sided: For some
reason, D&V
don't model or assign any 2-sided problems (except #8). We need
to
be used to them for later, so here are a few.
A: b) Use your green shoebox result to do a Two sided
test against
the null hypothesis p = .5.
Ch. 20, p.387 #7, Find the mistakes The
first mistake is that both hypotheses are written with incorrect
notation.
The second is that the alternative hypothesis is chosen wrongly.
I would write the company's goal as "more than 90% succeed"--I think
that
makes it clearer what structure to use.
Ch. 20, p.387 #8 Find the mistakes
From ActivStats, copied here:
MRA-304-2: Kerrich Coin Toss While he
was
a prisoner of the Germans during World War II, the British statistician
John Kerrich tossed a coin 10,000 times. He got 5067 heads.
Take Kerrich's tosses to be an SRS from the population of all possible
tosses of his coin. If the coin is perfectly balanced, p =
0.5.
Is there reason to think that Kerrich's coin was not balanced?
TRE-396-9: Store Checkout-Scanner Accuracy (adapted
from Activstats HW):
In a study of store checkout-scanners, 1234 items were checked and
20 of them were found to be overcharges (based on data from "UPC
Scanner
Pricing Systems: Are They Accurate?" by Goodstein, Journal of
Marketing,
Vol. 58). Before scanners were used, the overcharge rate was
estimated
to be about 1% . Based on these results, do scanners appear to give a different
rate of overcharges than the old method of keying in the price?
(All
items had to have individual price tags; scanning is much less
labor-intensive.)
Do the steps, finding the P-value and stating a conclusion.
= = = = = = = = = =
"Significance" Ch. 21, p. 404
1 P-value
3, 4 Alpha
5, 6 Significant?
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