Connie Hargrave's tree fell in the last storm and damaged the car of
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Answer:
The probability is 0.995 ( approx ).
Step-by-step explanation:
Let X represents the event of baby girl,
The probability of a baby being a girl is, p = 0.469,
So, the probability of a baby who is not a girl is, q = 1 - 0.469 = 0.531,
Also, the total number of experiment, n = 7
Thus, by the binomial distribution formula,
Where,
The probability that all babies are girl or there is no baby boy,
Hence, the probability that at least one of them is a boy = 1 - P(X=7)
= 1 - 0.00499125661758
= 0.995008743382
≈ 0.995
Answer: a. 1.981 < μ < 2.18
b. Yes.
Step-by-step explanation:
A. For this sample, we will use t-distribution because we're estimating the standard deviation, i.e., we are calculating the standard deviation, and the sample is small, n = 12.
First, we calculate mean of the sample:
2.08
Now, we estimate standard deviation:
s = 0.1564
For t-score, we need to determine degree of freedom and :
df = 12 - 1
df = 11
= 1 - 0.95
α = 0.05
0.025
Then, t-score is
= 2.201
The interval will be
±
2.08 ±
2.08 ± 0.099
The 95% two-sided CI on the mean is 1.981 < μ < 2.18.
B. We are 95% confident that the true population mean for this clinic is between 1.981 and 2.18. Since the mean number performed by all clinics has been 1.95, and this mean is less than the interval, there is evidence that this particular clinic performs more scans than the overall system average.