Answer:
97
Step-by-step explanation:
Given that:
Low = 43bpm
High = 115 bpm
Error = 3
α = 90%
To find the range estimate :
Standard destviation = (high - low) / 4
Standard deviation = (115 - 43) / 4
Standard deviation = 72/4 = 18
The sample size,(n) :
n = [(Zα/2 * sd)/E] ²
2 - tail = (Zα/2) = 1.645
[(Zα/2 * sd)/E] ² = [(1.645 * 18) / 3]² = (29.61/3)²
= 97.41
Sample size = 97
Answer is a hope it helps
If x is the amount of time Gillian takes,
1/10 - 1/x = 1/25
Therefore, the answer is A
Answer:
405
Step-by-step explanation:
To find sample size, use the following equation, where n = sample size, za/2 = the critical value, p = probability of success, q = probability of failure, and E = margin of error.

The values that are given are p = 0.84 and E = 0.03.
You can solve for the critical value which is equal to the z-score of (1 - confidence level)/2. Use the calculator function of invNorm to find the z-score. The value will given with a negative sign, but you can ignore that.
(1 - 0.9) = 0.1/2 = 0.05
invNorm(0.05, 0, 1) = 1.645
You can also solve for q which is 1 - p. For this problem q = 1 - 0.84 = 0.16
Plug the values into the equation and solve for n.

Round up to the next number, giving you 405.