Answer:
Option: C is the correct answer.
C. Buying a needle and buying thread are dependent events.
Step-by-step explanation:
let A denotes the events of buying a thread.
and B denote the event of buying a needle.
Then A∩B denote the event of buying a needle and a thread.
Also let P denote the probability of an event.
i.e. we are given:
P(A)=0.15
Also P(B|A)=0.25
As we know that:

As we know that when two events A and B are independent then,
P(A∩B)=∅
otherwise they are dependent events.
Hence, option: C is the correct answer.
Given Information:
Population mean = p = 60% = 0.60
Population size = N = 7400
Sample size = n = 50
Required Information:
Sample mean = μ = ?
standard deviation = σ = ?
Answer:
Sample mean = μ = 0.60
standard deviation = σ = 0.069
Step-by-step explanation:
We know from the central limit theorem, the sampling distribution is approximately normal as long as the expected number of successes and failures are equal or greater than 10
np ≥ 10
50*0.60 ≥ 10
30 ≥ 10 (satisfied)
n(1 - p) ≥ 10
50(1 - 0.60) ≥ 10
50(0.40) ≥ 10
20 ≥ 10 (satisfied)
The mean of the sampling distribution will be same as population mean that is
Sample mean = p = μ = 0.60
The standard deviation for this sampling distribution is given by

Where p is the population mean that is proportion of female students and n is the sample size.

Therefore, the standard deviation of the sampling distribution is 0.069.