The average daily volume of a computer stock in 2011 was μ = 35.1 million shares, according to a reliable source. A stock analyst believes that the stock volume in 2018 is different from the 2011 level. Based on a random sample of 30 trading days in 2018, he finds the sample mean to be 27.6 million shares, with a standard deviation of s = 11.4 million shares. Test the hypotheses by constructing a 95% confidence interval. Complete parts (a) through (c) below. (a) State the hypotheses for the test. Hoi H = 35.1 million shares H₁: H # 35.1 million shares (b) Construct a 95% confidence interval about the sample mean of stocks traded in 2018. million shares. With 95% confidence, the mean stock volume in 2018 is between million shares and (Round to three decimal places as needed.)

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**Average Daily Stock Volume Analysis**

**Introduction:**
The average daily volume of a computer stock in 2011 was \(\mu\) = 35.1 million shares, according to a reliable source. A stock analyst believes that the stock volume in 2018 is different from the 2011 level. Based on a random sample of 30 trading days in 2018, he finds the sample mean to be 27.6 million shares, with a standard deviation of \(s\) = 11.4 million shares. We will test the hypotheses by constructing a 95% confidence interval. Complete parts (a) through (c) below.

**(a) State the hypotheses for the test.**

\[
\begin{aligned}
H_0: \mu &= 35.1 \text{ million shares} \\
H_1: \mu &\neq 35.1 \text{ million shares}
\end{aligned}
\]

**(b) Construct a 95% confidence interval about the sample mean of stocks traded in 2018.**

With 95% confidence, the mean stock volume in 2018 is between \(\boxed{ }\) million shares and \(\boxed{ }\) million shares. (Round to three decimal places as needed.)

**Explanation:**
To construct the 95% confidence interval, we will use the formula for the confidence interval of the mean when the population standard deviation is unknown:

\[
\bar{x} \pm t \left( \frac{s}{\sqrt{n}} \right)
\]

Where:
- \(\bar{x}\) is the sample mean (27.6 million shares),
- \(s\) is the sample standard deviation (11.4 million shares),
- \(n\) is the sample size (30),
- \(t\) is the critical value from the t-distribution for 95% confidence with \(n - 1\) degrees of freedom (29 degrees of freedom).

1. Calculate the sample standard error:

\[
\frac{s}{\sqrt{n}} = \frac{11.4}{\sqrt{30}} \approx 2.081
\]

2. Determine the t-critical value for 95% confidence and 29 degrees of freedom. (Using a t-table or calculator, the value is approximately 2.045).

3. Calculate the margin of error:

\[
t \times
Transcribed Image Text:**Average Daily Stock Volume Analysis** **Introduction:** The average daily volume of a computer stock in 2011 was \(\mu\) = 35.1 million shares, according to a reliable source. A stock analyst believes that the stock volume in 2018 is different from the 2011 level. Based on a random sample of 30 trading days in 2018, he finds the sample mean to be 27.6 million shares, with a standard deviation of \(s\) = 11.4 million shares. We will test the hypotheses by constructing a 95% confidence interval. Complete parts (a) through (c) below. **(a) State the hypotheses for the test.** \[ \begin{aligned} H_0: \mu &= 35.1 \text{ million shares} \\ H_1: \mu &\neq 35.1 \text{ million shares} \end{aligned} \] **(b) Construct a 95% confidence interval about the sample mean of stocks traded in 2018.** With 95% confidence, the mean stock volume in 2018 is between \(\boxed{ }\) million shares and \(\boxed{ }\) million shares. (Round to three decimal places as needed.) **Explanation:** To construct the 95% confidence interval, we will use the formula for the confidence interval of the mean when the population standard deviation is unknown: \[ \bar{x} \pm t \left( \frac{s}{\sqrt{n}} \right) \] Where: - \(\bar{x}\) is the sample mean (27.6 million shares), - \(s\) is the sample standard deviation (11.4 million shares), - \(n\) is the sample size (30), - \(t\) is the critical value from the t-distribution for 95% confidence with \(n - 1\) degrees of freedom (29 degrees of freedom). 1. Calculate the sample standard error: \[ \frac{s}{\sqrt{n}} = \frac{11.4}{\sqrt{30}} \approx 2.081 \] 2. Determine the t-critical value for 95% confidence and 29 degrees of freedom. (Using a t-table or calculator, the value is approximately 2.045). 3. Calculate the margin of error: \[ t \times
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