AP Statistics 2017

(Marvins-Underground-K-12) #1
The conditions  needed  for the one sample  t   -test   are present.

(from   Table   B;  on  the TI-83/84,   tcdf(2.39,100,7)    =0.024  ).

Because P < 0.05,   reject  H   0   .   We  have    evidence    that,   in  identical   twins   reared  apart,  the better
educated twin is likely to have the higher IQ score.



  1.          a.   =  123.85, s = 9.07.   We  are told    that    the 20  cans    of  paint   have    been    randomly    selected.   It  is

    reasonable to assume that a sample of this size is small relative to the total population of such cans.
    A boxplot of the data shows no significant departures from normality. The conditions necessary to
    construct a 95% t confidence interval are present.




b.          We  are 95% confident   that    the true    mean    drying  time    for the paint   is  between 119.6   minutes and
128.1 minutes. Because 120 minutes is in this interval, we would not consider an average drying
time of 120 minutes for the population from which this sample was drawn to be unusual.

c.          

(On the TI-83/84,   we  find    P   -value  =   2   ×   tcdf(1.90,100,19) = 0.073.  )
d. We know that if a two-sided α -level significance test rejects (fails to reject) a null hypothesis,
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