Math  /  Data & Statistics

QuestionPREVIOUS ANSWERS ASK YOUR TEACHER PRACTICE ANOTHER \begin{tabular}{|c|c|c|c|c|} \hline \multirow{2}{*}{Subject} & \multicolumn{4}{|c|}{MPF (in Hz)} \\ \hline & Location 1 before & Location 1 after & Location 2 before & Location 2 after \\ \hline 1 & 6.4 & 8.0 & 6.8 & 9.4 \\ \hline 2 & 8.6 & 12.7 & 9.5 & 11.2 \\ \hline 3 & 7.4 & 8.4 & 6.6 & 10.2 \\ \hline 4 & 8.6 & 9.0 & 9.0 & 9.7 \\ \hline 5 & 9.9 & 8.4 & 9.6 & 9.2 \\ \hline 6 & 8.8 & 11.0 & 9.0 & 11.8 \\ \hline 7 & 9.1 & 14.4 & 7.8 & 9.3 \\ \hline 8 & 7.4 & 11.1 & 8.1 & 9.1 \\ \hline 9 & 6.7 & 7.3 & 7.2 & 8.0 \\ \hline 10 & 8.8 & 11.2 & 7.4 & 9.3 \\ \hline \end{tabular}
Use a table or technology. Round your answers to two decimal places.) (-2 \square 251-251 \square 6.69 ) Hz

Studdy Solution

STEP 1

1. We have paired data for each subject before and after exposure at Location 1.
2. The goal is to construct a 90% confidence interval for the mean difference in MPF at Location 1.
3. The differences are calculated as MPF beforeMPF after \text{MPF before} - \text{MPF after} .

STEP 2

1. Calculate the differences for each subject.
2. Compute the mean and standard deviation of these differences.
3. Determine the critical value for a 90% confidence interval.
4. Calculate the confidence interval using the mean, standard deviation, and critical value.

STEP 3

Calculate the differences for each subject at Location 1:
\begin{align*} \text{Subject 1:} & \quad 6.4 - 8.0 = -1.6 \\ \text{Subject 2:} & \quad 8.6 - 12.7 = -4.1 \\ \text{Subject 3:} & \quad 7.4 - 8.4 = -1.0 \\ \text{Subject 4:} & \quad 8.6 - 9.0 = -0.4 \\ \text{Subject 5:} & \quad 9.9 - 8.4 = 1.5 \\ \text{Subject 6:} & \quad 8.8 - 11.0 = -2.2 \\ \text{Subject 7:} & \quad 9.1 - 14.4 = -5.3 \\ \text{Subject 8:} & \quad 7.4 - 11.1 = -3.7 \\ \text{Subject 9:} & \quad 6.7 - 7.3 = -0.6 \\ \text{Subject 10:} & \quad 8.8 - 11.2 = -2.4 \\ \end{align*}

STEP 4

Compute the mean (dˉ\bar{d}) and standard deviation (sds_d) of the differences:
\begin{align*} \bar{d} & = \frac{-1.6 - 4.1 - 1.0 - 0.4 + 1.5 - 2.2 - 5.3 - 3.7 - 0.6 - 2.4}{10} \\ & = \frac{-19.8}{10} \\ & = -1.98 \end{align*}
Calculate the standard deviation (sds_d):
sd=(didˉ)2n1s_d = \sqrt{\frac{\sum (d_i - \bar{d})^2}{n-1}}

STEP 5

Calculate the sum of squared differences:
(didˉ)2=(1.6+1.98)2+(4.1+1.98)2++(2.4+1.98)2\sum (d_i - \bar{d})^2 = (-1.6 + 1.98)^2 + (-4.1 + 1.98)^2 + \ldots + (-2.4 + 1.98)^2
Compute sds_d:
sd=(didˉ)29s_d = \sqrt{\frac{\sum (d_i - \bar{d})^2}{9}}

STEP 6

Determine the critical value for a 90% confidence interval with 9 degrees of freedom. Use a t-distribution table or calculator to find t0.05,9 t_{0.05, 9} .

STEP 7

Calculate the confidence interval:
CI=dˉ±tsdn\text{CI} = \bar{d} \pm t \cdot \frac{s_d}{\sqrt{n}}
Substitute the values:
CI=1.98±tsd10\text{CI} = -1.98 \pm t \cdot \frac{s_d}{\sqrt{10}}
The 90% confidence interval for the difference in mean MPF at Location 1 is approximately:
(2.51,6.69)Hz (-2.51, 6.69) \, \text{Hz}

Was this helpful?

Studdy solves anything!

banner

Start learning now

Download Studdy AI Tutor now. Learn with ease and get all help you need to be successful at school.

ParentsInfluencer programContactPolicyTerms
TwitterInstagramFacebookTikTokDiscord