Answer:
The F-Ratio increases as, the variability between means increases relative to the variability within groups
Step-by-step explanation:
The F-Ratio is given as follows;

Where;
= The variance between groups
= The variance within groups
Therefore, as the F-Ratio increases, the variability between groups (means) increases relation to the variability within groups
The answer would be D. Survey a random sample of persons within each geographical region of the city.
This is because the other 3 answers are biased samples of data, which could sway the data collected and/or the decision that is made upon it.
Hope this helps! :)
Answer: the incubation time that separates the bottom 2.5% from the rest of the incubation times is 24.96 days.
Step-by-step explanation:
Suppose the incubation times are approximately normally distributed, we would apply the formula for normal distribution which is expressed as
z = (x - µ)/σ
Where
x = incubation times.
µ = mean time
σ = standard deviation
From the information given,
µ = 23 days
σ = 1 day
The probability value for the incubation time that separates the bottom 2.5% from the rest of the incubation times would be (1 - 2.5/100) = (1 - 0.025) = 0.975
Looking at the normal distribution table, the z score corresponding to the probability value is 1.96
Therefore,
1.96 = (x - 23)/1
x = 1.96 + 23
x = 24.96
He paid $6.42 per bag. $25.81 - $6.55 = $19.26. $19.26/3 = $6.42