Transcript When Normal or n > 30 and is known

Section
8.2
Testing the Mean 
Testing …
When Normal or n > 30 and  is known use this test
statistic:
Then find the p-value. (Normalcdf)
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Testing …
When Normal or n > 30 and  is unknown use this test
statistic:
1. State H0 and H1 and α
2. Use this test statistic:
3. Go to 2nd vars  tcdf (lower, upper, d.f.) = p-value
4. Reject or Fail to Reject H0 and conclude about the
claim H1
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Ex: 1
Sunspots (dark spots that appear on the surface of the sun).
x: avg # of sunspots observed in a four-week period
A random sample of 40 from Spanish colonial times gave:
mean of 47.0 and st. dev of 37.5.
For thousands of yrs, the avg # of sunspots is 41.
Does the data indicate sunspots during that period was
higher?
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Ex: 2
Archaeologists have known the mean length of arrowheads
at a site is 2.6 cm.
A random sample of 61 arrowheads beyond some cliff gave
an avg. length of 2.92 cm and st. dev. of 0.85 cm.
Does the data indicate the avg. length of arrowheads in
that area is longer? Use α = 0.01.
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Ex: 3
The drug 6-mP is used to treat leukemia.
Remission times (symptoms of disease are reduced)
(in weeks) for a random sample of 21 patients using it:
The time are normal.
A previous drug had avg. remission time of 12.5 weeks.
Does the data indicate mean remission time for 6-mP is different
the previous drug? Use  = 0.01.
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