Answer:
20x=90
divide both sides by 20 x=90÷20
so x is 4.5
Using the t-distribution, as we have the standard deviation for the sample, it is found that the 95% confidence interval for the number of units students in their college are enrolled in is (11.7, 12.7).
<h3>What is a t-distribution confidence interval?</h3>
The confidence interval is:
![\overline{x} \pm t\frac{s}{\sqrt{n}}](https://tex.z-dn.net/?f=%5Coverline%7Bx%7D%20%5Cpm%20t%5Cfrac%7Bs%7D%7B%5Csqrt%7Bn%7D%7D)
In which:
is the sample mean.
- s is the standard deviation for the sample.
The critical value, using a t-distribution calculator, for a two-tailed <em>95% confidence interval</em>, with 49 - 1 = <em>48 df</em>, is t = 2.0106.
Hence:
![\overline{x} - t\frac{s}{\sqrt{n}} = 12.2 - 2.0106\frac{1.6}{\sqrt{49}} = 11.7](https://tex.z-dn.net/?f=%5Coverline%7Bx%7D%20-%20t%5Cfrac%7Bs%7D%7B%5Csqrt%7Bn%7D%7D%20%3D%2012.2%20-%202.0106%5Cfrac%7B1.6%7D%7B%5Csqrt%7B49%7D%7D%20%3D%2011.7)
![\overline{x} + t\frac{s}{\sqrt{n}} = 12.2 + 2.0106\frac{1.6}{\sqrt{49}} = 12.7](https://tex.z-dn.net/?f=%5Coverline%7Bx%7D%20%2B%20t%5Cfrac%7Bs%7D%7B%5Csqrt%7Bn%7D%7D%20%3D%2012.2%20%2B%202.0106%5Cfrac%7B1.6%7D%7B%5Csqrt%7B49%7D%7D%20%3D%2012.7)
The 95% confidence interval for the number of units students in their college are enrolled in is (11.7, 12.7).
More can be learned about the t-distribution at brainly.com/question/16162795
Answer:
An object, person or endeavor in a state of failure A serious, unexpected, and often dangerous situation requiring immediate action A person harmed or killed as a result of an unfortunate event or action
Explanation:
Based on the information given regarding the advertising firm, it can be noted that the firm is at step 4 of the data analysis process.
<h3>
What is data analysis?</h3>
Data analysis simply means the collection and analysis of data in order to reach a particular conclusion or get certain information.
In this case, since the advertising firm has used insights from its analytics team to create a strategy for improving sales. This is the 4th step which is known as "analyze the data".
Learn more about advertisement on:
brainly.com/question/1658517