estimate how much parents spend on their kids birt opulation standard deviation is approximately o restimate is within 4 dollar(s) of average spending u have to sample?

MATLAB: An Introduction with Applications
6th Edition
ISBN:9781119256830
Author:Amos Gilat
Publisher:Amos Gilat
Chapter1: Starting With Matlab
Section: Chapter Questions
Problem 1P
icon
Related questions
Question

need help please!!

### Sample Size Determination for Estimating Parental Spending on Kids' Birthday Parties

**Objective:**
To estimate how much parents spend on their kids' birthday parties using a sample size that ensures a specified confidence level and margin of error.

**Scenario:**
You want to obtain a sample to estimate how much parents spend on their kids' birthday parties. Based on a previous study, you believe the population standard deviation is approximately \( \sigma = 34.6 \) dollars. You would like to be 90% confident that your estimate is within 4 dollar(s) of average spending on the birthday parties. 

**Question:**
How many parents do you have to sample?

**Formula:**
To find the necessary sample size \( n \), we use the following formula derived from the margin of error for a population mean:

\[ n = \left ( \frac{Z_{\alpha/2} \cdot \sigma}{E} \right )^2 \]

Where:
- \( Z_{\alpha/2} \) is the Z-value that corresponds to the desired confidence level.
- \( \sigma \) is the population standard deviation.
- \( E \) is the margin of error.

For a 90% confidence level, the corresponding \( Z_{\alpha/2} \) value is approximately 1.645. Given:
- Population standard deviation, \( \sigma = 34.6 \) dollars.
- Desired margin of error, \( E = 4 \) dollars.

You can plug these values into the formula to calculate the required sample size \( n \).

**Calculation:**
\[ n = \left ( \frac{1.645 \cdot 34.6}{4} \right )^2 \]

**Result:**
\[ n = \left ( \frac{56.977}{4} \right )^2 = \left ( 14.24425 \right )^2 \approx 203 \]

Thus, you need to sample approximately **203 parents** to estimate how much parents spend on their kids' birthday parties with 90% confidence and a margin of error of 4 dollars.
Transcribed Image Text:### Sample Size Determination for Estimating Parental Spending on Kids' Birthday Parties **Objective:** To estimate how much parents spend on their kids' birthday parties using a sample size that ensures a specified confidence level and margin of error. **Scenario:** You want to obtain a sample to estimate how much parents spend on their kids' birthday parties. Based on a previous study, you believe the population standard deviation is approximately \( \sigma = 34.6 \) dollars. You would like to be 90% confident that your estimate is within 4 dollar(s) of average spending on the birthday parties. **Question:** How many parents do you have to sample? **Formula:** To find the necessary sample size \( n \), we use the following formula derived from the margin of error for a population mean: \[ n = \left ( \frac{Z_{\alpha/2} \cdot \sigma}{E} \right )^2 \] Where: - \( Z_{\alpha/2} \) is the Z-value that corresponds to the desired confidence level. - \( \sigma \) is the population standard deviation. - \( E \) is the margin of error. For a 90% confidence level, the corresponding \( Z_{\alpha/2} \) value is approximately 1.645. Given: - Population standard deviation, \( \sigma = 34.6 \) dollars. - Desired margin of error, \( E = 4 \) dollars. You can plug these values into the formula to calculate the required sample size \( n \). **Calculation:** \[ n = \left ( \frac{1.645 \cdot 34.6}{4} \right )^2 \] **Result:** \[ n = \left ( \frac{56.977}{4} \right )^2 = \left ( 14.24425 \right )^2 \approx 203 \] Thus, you need to sample approximately **203 parents** to estimate how much parents spend on their kids' birthday parties with 90% confidence and a margin of error of 4 dollars.
Expert Solution
steps

Step by step

Solved in 4 steps with 4 images

Blurred answer
Recommended textbooks for you
MATLAB: An Introduction with Applications
MATLAB: An Introduction with Applications
Statistics
ISBN:
9781119256830
Author:
Amos Gilat
Publisher:
John Wiley & Sons Inc
Probability and Statistics for Engineering and th…
Probability and Statistics for Engineering and th…
Statistics
ISBN:
9781305251809
Author:
Jay L. Devore
Publisher:
Cengage Learning
Statistics for The Behavioral Sciences (MindTap C…
Statistics for The Behavioral Sciences (MindTap C…
Statistics
ISBN:
9781305504912
Author:
Frederick J Gravetter, Larry B. Wallnau
Publisher:
Cengage Learning
Elementary Statistics: Picturing the World (7th E…
Elementary Statistics: Picturing the World (7th E…
Statistics
ISBN:
9780134683416
Author:
Ron Larson, Betsy Farber
Publisher:
PEARSON
The Basic Practice of Statistics
The Basic Practice of Statistics
Statistics
ISBN:
9781319042578
Author:
David S. Moore, William I. Notz, Michael A. Fligner
Publisher:
W. H. Freeman
Introduction to the Practice of Statistics
Introduction to the Practice of Statistics
Statistics
ISBN:
9781319013387
Author:
David S. Moore, George P. McCabe, Bruce A. Craig
Publisher:
W. H. Freeman