A group of 20 students attempting a MathematicalChallenge have an average age of 11. When their teacher is included their averag
2 answers:
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<h2>Answer:</h2>
The probability that the customer did not try on the t- shirt is:
0.2432
<h2>Step-by-step explanation:</h2>It is given that the probability that a customer tries a t-shirt is: 0.40
After he will try
The probability that he will buy the t-shirt is: 0.70
The probability that he will not try t-shirt is: 1-0.40=0.60
If he will not try
then the probability of buying a t-shirt is: 0.15
This means that the total probability of Buying a t-shirt is:
0.40×0.70+0.60×0.15
= 0.37
It is given that the customer bought a t-shirt, we need to find the probability that he did not try the t-shirt:
The probability is given by:
Answer:
The 95% confidence interval for the mean score is:
∈
Step-by-step explanation:
We want to estimate the population mean, that is, the average score of all the subjects.
An estimator for the population mean μ is
Since the sample size is then we use the statistic
with
degrees of freedom
The confidence interval for the mean is:
Where
is the average score of the sample
is the standard deviation of the sample
is the sample size
for a confidence level of 95% and 26 degrees of freedom
Then confidence interval is
∈