Find the product. (2n + 2)(2n

54 equals 9 more than a number t .

aleksandr82 [10.1K]

Answer:

t=45

Step-by-step explanation:

54=t+9

54-9=t

t=45

6 0

1 year ago

The results of a mathematics placement exam at two different campuses of Mercy College follow: Campus Sample Size Sample Mean Po

Leona [35]

Answer:

$z=\frac{(33-31)-0}{\sqrt{\frac{8^2}{330}+\frac{7^2}{310}}}}=3.37$

$p_v =P(Z>3.37)=1-P(Z$

Comparing the p value with a significance level for example $\alpha=0.05$ we see that $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis, and we can say that the mean for the Campus 1 is significantly higher than the mean for the group 2.

Step-by-step explanation:

Data given

Campus Sample size Mean Population deviation

1 330 33 8

2 310 31 7

$\bar X_{1}=33$ represent the mean for sample 1

$\bar X_{2}=31$ represent the mean for sample 2

$\sigma_{1}=8$ represent the population standard deviation for 1

$\sigma_{2}=7$ represent the population standard deviation for 2

$n_{1}=330$ sample size for the group 1

$n_{2}=310$ sample size for the group 2

$\alpha$ Significance level provided

z would represent the statistic (variable of interest)

Concepts and formulas to use

We need to conduct a hypothesis in order to check if the mean for Campus 1 is higher than the mean for Campus 2, the system of hypothesis would be:

Null hypothesis: $\mu_{1}-\mu_{2}\leq 0$

Alternative hypothesis: $\mu_{1} - \mu_{2}> 0$

We have the population standard deviation's, and the sample sizes are large enough we can apply a z test to compare means, and the statistic is given by:

$z=\frac{(\bar X_{1}-\bar X_{2})-\Delta}{\sqrt{\frac{\sigma^2_{1}}{n_{1}}+\frac{\sigma^2_{2}}{n_{2}}}}$ (1)

z-test: Is used to compare group means. Is one of the most common tests and is used to determine whether the means of two groups are equal to each other.

With the info given we can replace in formula (1) like this:

$z=\frac{(33-31)-0}{\sqrt{\frac{8^2}{330}+\frac{7^2}{310}}}}=3.37$

P value

Since is a one right tailed test the p value would be:

$p_v =P(Z>3.37)=1-P(Z$

Comparing the p value with a significance level for example $\alpha=0.05$ we see that $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis, and we can say that the mean for the Campus 1 is significantly higher than the mean for the group 2.

5 0

2 years ago

Students who party before an exam are twice as likely to fail as those who don't party (and presumably study). If 20% of the stu

True [87]

Answer:

The fraction of the students who failed to went partying = $\frac{1}{10}$

Step-by-step explanation:

Let total number of students = 100

No. of students partied are twice the no. of students who not partied.

⇒ No. of students partied = 2 × the no. of students who are not partied

No. of students partied before the exam = 20 % of total students

⇒ No. of students partied before the exam = $\frac{20}{100}$ × 100

⇒ No. of students partied before the exam = 20

No. of students who not partied before the exam = $\frac{20}{2} = 10$

Thus the fraction of the students who failed to went partying = $\frac{10}{100} = \frac{1}{10}$

8 0

2 years ago

Explain why the vertical line test is used to determine if a graph represents a function.

Aleksandr [31]

Hi there Mary Dominguez, So what a vertical line test down is to find out if a particular graph is a function or not. What you do is take a vertical strait line and move it right to left or left to right, depending on your preference, along the X axis. The reason this works is a function can not have an x that has 2 different y values. If we use the vertical line test on a graph with say a graph that has (2,3) and (2,4) we can use the vertical line test and see that the line hits 2 points at once which means its not a function :)

4 0

2 years ago

Read 2 more answers

Emma needs to divide 7 by 1/2. Which strategy can Emma use to get the answer?

Juliette [100K]

Answer:

14

Step-by-step explanation:

Convert the fraction into a decimal

1/2 = 0.5

Divide

7/0.5 = 14

7 0

2 years ago

Find the product. (2n + 2)(2n – 2)