Math Problem Statement
Both of your confidence interval limits are incorrect. The confidence interval for the estimate of
muμ
is
x overbar minus Upper E less than mu less than x overbar plus Upper Ex−E<μ<x+E,
where E is the margin of error, and
x overbarx
is the sample mean. The margin of error is given by the formula below, where
t Subscript alpha divided by 2tα/2
is the critical t value separating an area of
alpha divided by 2α/2
in the right tail of the Student t distribution, and
dfequals=nminus−1
is the number of degrees of freedom.
Upper E equals t Subscript alpha divided by 2 Baseline times StartFraction s Over StartRoot n EndRoot EndFraction left parenthesis Use df equals n minus 1 right parenthesisE=tα/2•sn (Use df=n−1)
If using a table of critical t-values to find a critical value of
t Subscript alpha divided by 2tα/2,
but the table does not include the number of degrees of freedom, the closest value could be used, the next lower number of degrees of freedom found in the table could be used as a conservative value, or interpolation could be used.
Alternatively, technology can be used to find the confidence interval. Make sure to round to one decimal place.
Solution
Thank you for the clarification. Let's recalculate the 90% confidence interval for the mean pulse rate of adult females using the t-distribution.
Steps for Calculation
- Calculate the sample mean () and sample standard deviation () for the female pulse rates.
- Determine the critical t-value () for a 90% confidence interval with .
- Compute the margin of error ().
- Construct the confidence interval.
Step 1: Calculate the Sample Mean and Sample Standard Deviation
Pulse rates for females: 79, 87, 85, 81, 80, 77, 76, 86, 74, 95, 90, 64, 89, 92, 66, 72, 62, 84, 65, 64, 60, 74, 55, 68, 67, 67, 57, 77
Calculate the Mean ():
Calculate the Sample Standard Deviation ():
Step 2: Determine the Critical t-Value
For a 90% confidence interval with , the critical t-value () can be found using a t-table or a calculator. For 27 degrees of freedom and a 90% confidence level, .
Step 3: Compute the Margin of Error
Step 4: Construct the Confidence Interval
Final Answer
The 90% confidence interval for the mean pulse rate for adult females is:
Would you like more details or have any questions? Here are five related questions you might want to explore:
- How do you calculate a confidence interval for a population proportion?
- What is the difference between a z-distribution and a t-distribution?
- How do you determine the sample size needed for a specific margin of error?
- What assumptions are necessary for constructing confidence intervals?
- How do you interpret confidence intervals in hypothesis testing?
Tip: Always ensure the sample data is randomly selected and representative of the population to make valid inferences.
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Math Problem Analysis
Mathematical Concepts
Statistics
Confidence Intervals
T-Distribution
Formulas
Confidence Interval Formula: x̄ - E < μ < x̄ + E
Margin of Error: E = tα/2 * (s / √n)
Theorems
Student's t-Distribution
Suitable Grade Level
Undergraduate