O-1a) 40% of the sales agents had sales of $300,000 or less.
O-1b) 10% (show work!)
O-1c) No agents had sales between $1 million and $1.1 million
O-1d) $800,000 (with explanation!)
O-2a) 2-prop z-interval (name or formula)
success = 188, 180 > 10
failures = 12, 20 > 10
Independent samples
(-0.0156, 0.0956)
We are 96% confident that the difference in the proportions of parts meeting specs for the two shifts is between -0.0156 and 0.0956.
O-2b) No, because 0 is in the interval, zero is a possible value. So we are 96% confident that zero difference in shift specs is possible. We make this decision using alpha = 0.04!!
O-3a) z > 1.14 = 12.71%
O-3b) 1 - (8729)^5
O-3c) invnorm(0.99) = 2.33
algebra: (291.2 - M)/2.8 = 2.33
M =
Show work!!!
O-4): matched pairs t-test
Ho: mu = 0
Ha: mu > 0 (mean diff (after - before) is greater than 0)
Name or formula: t = (x-bar - 0)/(s/sqrt(n))
SRS and graph to check nearly normal
t = 3.75
df = 11
p-value = 0.002
Reject Ho. Is evidence that people who complete program have increased dexterity.
O-5a)
rv: amount of draft
treatments: standard hitch and new hitch
experimental units: 2 large plots of land
O-5b)
Yes, the hitches are randomly assigned to the plots.
O-5c)
No. Each treatment was applied to only one plot. Replication is needed.
O-5d)
Even though 25 measurements were taken, each hitch was used on only one plot only. If a difference in the draft is observed, we will not know whether the difference is due to the hitch or the plot. The treatment (hitches) are confounded with the plots.
