A shopkeeper buys.rs 250 and sell it for rs 285 gain or loss

A random sample of 50 recent college graduates results in a mean time to graduate of 4.58 years, with a standard deviation of 1.

Anna007 [38]

Answer:

The 90% confidence interval for the mean time to graduate with a bachelor’s degree is (4.32, 4.84).

Yes, this confidence interval contradict the belief that it takes 4 years to complete a bachelor’s degree.

Step-by-step explanation:

The (1 - α)% confidence interval for population mean μ, when the population standard deviation is not known is:

$CI=\bar x\pm t_{\alpha/2, (n-1)}\times \frac{s}{\sqrt{n}}$

The information provided is:

$\bar x=4.58\\s=1.10\\\alpha =0.10$

Compute the critical value of t for 90% confidence interval and (n - 1) degrees of freedom as follows:

$t_{\alpha/2, (n-1)}=t_{0.10/2, (50-1)}=t_{0.05, 49}=1.671$

*Use a t-table for the probability.

Compute the 90% confidence interval for population mean μ as follows:

$CI=\bar x\pm t_{\alpha/2, (n-1)}\times \frac{s}{\sqrt{n}}$

$=4.58\pm 1.671\times \frac{1.10}{\sqrt{50}}\\=4.58\pm 0.26\\=(4.32, 4.84)$

Thus, the 90% confidence interval for the mean time to graduate with a bachelor’s degree is (4.32, 4.84).

If a hypothesis test is conducted to determine whether it takes 4 years to complete a bachelor’s degree or not, the hypothesis will be:

Hₐ: The mean time it takes to complete a bachelor’s degree is 4 years, i.e. μ = 4.

Hₐ: The mean time it takes to complete a bachelor’s degree is different from 4 years, i.e. μ ≠ 4.

The decision rule based on a confidence interval will be:

Reject the null hypothesis if the null value is not included in the interval.

The 90% confidence interval for the mean time to graduate with a bachelor’s degree is (4.32 years, 4.84 years).

The null value, i.e. μ = 4 is not included in the interval.

The null hypothesis will be rejected at 10% level of significance.

Thus, it can be concluded that that time it takes to complete a bachelor’s degree is different from 4 years.

4 0

3 years ago

Ephraim took a friend for a birthday dinner. The total bill for dinner was $30.29 (including tax and a tip). If Ephraim paid a 2

notka56 [123]

Answer:

$x= 30.29 (1-0.223) = 23.54$

Ephraim paid a 22.3% tip, what was his bill before adding the tip?

23.54

Step-by-step explanation:

For this case we assume the following notation:

$T= 30.29$ represent the total paid for the dinner

x represent the amount before adding the tip

f =0.223 represent the fraction of the total amount destined to the tip

Based on this we can create the following relationship between T and x:

$T = f*T + (1-f)T = f*T + x$

And we can solve for x from the previous equation like this:

$x = T - f*T$

Taking T common factor we got:

$x = T (1-f)$

And if we replace we got:

$x= 30.29 (1-0.223) = 23.54$

And the amount destined to the tip would be $fT = 0.223*30.29=6.75$

And if we add the two values we see that:

23.54+6.75 = 30.29 representing the total cost.

So then the correct answer for the question:

Ephraim paid a 22.3% tip, what was his bill before adding the tip?

23.54

4 0

3 years ago

I play cooking fever seven times as much as I play spider solitaire. If I play both games 32 hours a week how many hours do I pl

Feliz [49]

To much lol u need 2 pick up a book or go outside

6 0

3 years ago

At a quiz competition, for every question teamA answered correctly, team B answered 2 questions correctly. The ratio of the numb

vekshin1

Answer:

the answer would be 3. 1 to 2

Step-by-step explanation:

Because for every one answer the team A gets, team B gets 2 so it is a 1 to 2 ratio

7 0

3 years ago

Can anybody answer Kailey correctly graphed the opposite of -3.3 on the number line?

Alexus [3.1K]

Answer:

where is the graph????

6 0

3 years ago