Here is my answer, hope to help you
Answer:
75
Step-by-step explanation:
convert percent to decimal
20% = 0.20
15 / 0.20 = 75
Answer with explanation:
The 90% confidence interval (51%, 61%) for proportion means that the proportion of getting heads lie in it.
Given : Total number of times coin is tossed = 250
Number of times they got head =140
The probability of getting a head = 0.56
The confidence interval for proportion is given by :-

Given significance level : 
Critical value : 
Now, the 90% confidence interval for proportion will be :-

Hence, the given confidence interval is correct.