177k views
3 votes
In a recent year, the average movie ticket cost $7.89. In a random sample of 50 movie tickets from various areas, what is the probability that the mean cost is between $7.00 and $7.50, given that the population standard deviation is $1.39?

1 Answer

1 vote

Final answer:

To calculate the probability that the mean cost of movie tickets in a sample is between $7.00 and $7.50, we determine the standard error, calculate the z-scores for both price limits, and then find the corresponding probabilities using the standard normal distribution. The probability is the difference between these probabilities.

Step-by-step explanation:

To solve this problem, you can use the concepts of the sampling distribution of the sample mean and the Central Limit Theorem (CLT). Given that the population standard deviation (σ) is $1.39 and the sample size (n) is 50, we can assume that the sample mean will be normally distributed based on the CLT as n ≥ 30.

The first step is to calculate the standard error (SE) of the mean, which is the standard deviation (σ) divided by the square root of the sample size (n):
SE = σ / √ n
SE = $1.39 / √ 50
SE ≈ $0.1964

Next, we can find the z-scores for the lower and upper bounds of the movie ticket cost ($7.00 and $7.50 respectively) using the following formula:
z = (X - μ) / SE
Here X is the value for which you want to find the z-score, and μ is the population mean. For $7.00:
z = ($7.00 - $7.89) / $0.1964
z ≈ -4.53
And for $7.50:
z = ($7.50 - $7.89) / $0.1964
z ≈ -1.98

Now, using the standard normal distribution table, we can find the probabilities corresponding to these z-scores and then find the probability that the sample mean falls between $7.00 and $7.50 by finding the difference between the two probabilities.

User Paul Ardeleanu
by
8.2k points

No related questions found

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

9.4m questions

12.2m answers

Categories