Question
please show work thanks!
For each situation, state the null and alternative hypotheses: (Type "mu" for the symbol mu, e.g. mu > 1 for the mean is greater then 1, mu = 1 for the mean is greater then or equal to 1. Please do not include units such as "mm" or "$" in your answer.) (a) The manufacturer claims the diameter of a spindle in a small motor is supposed to be 6.5 millimeters (mm) with a standard deviation of 0.19 mm. If the spindle is either too small or too large, the motor will not work properly. The manufacturer measures the diameter in a sample of 20 spindles to determine whether the mean diameter has moved away from the required measurement. Suppose the sample has an average diameter of 6.61 mm. H_0: H_a: (b) Harry thinks thet prices in Caldwell are lower then the rest of the country. He reads thet the nationwide average price of a certain brand of laundry detergent is $20.15 with standard deviation $1.36. He takes a sample from 3 local Caldwell stores and finds the average price for this same brand of detergent is $22.87. H_0: H_a:
Explanation / Answer
a)
"If the spindle is too small or too large, the motor will not work properly."
Hence, it is a two tailed test,
Ho: u = 6.5
Ha: u =/= 6.5 [ANSWER]
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b)
"...prices in Caldwell are lower..."
Hence, to disprove this, this is a right tailed test. So,
Ho: u <= 20.15
Ha: u > 20.15 [ANSWER]
