Answer:
Her weight before was 100kg.
Step-by-step explanation:
This question can be solved using a rule of three.
Amy finds that her weight has decreased by 25%
So her weight is 100-25 = 75% = 0.75 of the original amount(what it was before).
Her current weight is 75kg.
Her previous weight was x, which is 100% = 1.
So
75 - 0.75
x - 1
Her weight before was 100kg.
Answer:
107,426, bigger
Step-by-step explanation:
Given that a soccer ball manufacturer wants to estimate the mean circumference of soccer balls within 0.05 in.
Margin of error = 0.05 inches
Since population std deviation is known we can use z critical value.
(a) i.e. for 99% confidence interval
Z critical = 2.58
A minimum sample size of 107 needed.
b)
Here minimum sample size = 426
Due to the increased variability in the population, a bigger sample size is needed to ensure the desired accuracy.