Prestone Coolant is the number 1 coolant/antifreeze in the United States. Prestone Coolant provides guaranteed corrosion protection for 150,000 miles/10 years, as well as protection in all extremes from -37°C to 129°C.
Prestone Coolant is made using ethylene glycol, diethylene glycol, hexanoic acid, neodecanoic acid, water, sodium hydroxide, tolyltriazole, dye, propanol, and PPG. The formulation specifically states that a one-gallon container of Prestone Coolant should contain 80% ethylene glycol.
A quality control manager at Prestone needs to make sure that this specification is being met, so he wants to draw a simple random sample of gallon containers of Prestone Coolant and measure the actual proportion/percentage of ethylene glycol in each gallon container. Determine how many gallon containers of Prestone Coolant he needs to sample if he wants to be 97% confident of being within 4% of the true proportion/percentage of ethylene glycol in all of the gallon containers. Use .80 as your best estimate of the “true” population proportion, π.
Answer: n = _____ gallon containers of Prestone Coolant need to be sampled
The following information is provided,
Significance Level, α = 0.03, Margin of Error, E = 0.04
The provided estimate of proportion p is, p = 0.8
The critical value for significance level, α = 0.03 is 2.17.
The following formula is used to compute the minimum sample size
required to estimate the population proportion p within the
required margin of error:
n >= p*(1-p)*(zc/E)^2
n = 0.8*(1 - 0.8)*(2.17/0.04)^2
n = 470.89
Therefore, the sample size needed to satisfy the condition n
>= 470.89 and it must be an integer number, we conclude that the
minimum required sample size is n = 471
Ans : Sample size, n = 471
Prestone Coolant is the number 1 coolant/antifreeze in the United States. Prestone Coolant provides guaranteed corrosion...