Someone help on number 5 please

You know that 3+3+3+3=4*3=12.this shows that 4 groups of 3 equal 12. The expression x +x+x+x+=4x means x is used as an addend 4

Anarel [89]

Answer:

4m

Step-by-step explanation:

4 0

3 years ago

Find the height of the cone. Round your answer to the nearest whole number.

amm1812

Answer:

3

Step-by-step explanation:

3.34in is ans and after rounding off we can get 3

3 0

3 years ago

Find f(-5) f(x) -4x + 3

Fiesta28 [93]

Answer:

if f(x)= -4x+3

f(-5)= 23

Step-by-step explanation:

first you substitute x for -5

f(-5)= -4(-5)+3

then you multiply

-4(-5)

f(-5)=20+3

you get the positive 20 because negative times negative equals positive

then you just add the rest (20+3) which will give you your answer

f(-5)= 23

8 0

3 years ago

A researcher for an airline interviews all of the passengers on five randomly selected flights.

antoniya [11.8K]

Answer

Cluster sampling. See explanation below.

Step-by-step explanation:

For this case they not use random sampling since we are selecting people from flights. Because we select just 5 random flights.

Is not stratified sampling since we don't have strata clearly defined on this case, and other important thing is that in order to apply this method we need homogeneous strata groups and that's not satisfied on this case.

Is not convenience sampling because they NOT use a non probability method in order to select the people from the flights.

So then the only possible method is cluster sampling since we have clusters clearly defined (Passengers from the airlines), and we satisfy the condition of homogeneous characteristics on the clusters and an equal chance of being a part of the sample, since we are selecting RANDOMLY, the 5 flights to take the information.

6 0

3 years ago

Lightbulbs of a certain type are advertised as having an average lifetime of 750 hours. The price of these bulbs is very favorab

Katyanochek1 [597]

Answer:

(a) Customer will not purchase the light bulbs at significance level of 0.05

(b) Customer will purchase the light bulbs at significance level of 0.01 .

Step-by-step explanation:

We are given that Light bulbs of a certain type are advertised as having an average lifetime of 750 hours. A random sample of 50 bulbs was selected, and the following information obtained:

Average lifetime = 738.44 hours and a standard deviation of lifetimes = 38.2 hours.

Let Null hypothesis, $H_0$ : $\mu$ = 750 {means that the true average lifetime is same as what is advertised}

Alternate Hypothesis, $H_1$ : $\mu$ < 750 {means that the true average lifetime is smaller than what is advertised}

Now, the test statistics is given by;

T.S. = $\frac{Xbar-\mu}{\frac{s}{\sqrt{n} } }$ ~ $t_n_-_1$

where, X bar = sample mean = 738.44 hours

s = sample standard deviation = 38.2 hours

n = sample size = 50

So, test statistics = $\frac{738.44-750}{\frac{38.2}{\sqrt{50} } }$ ~ $t_4_9$

= -2.14

(a) Now, at 5% significance level, t table gives critical value of -1.6768 at 49 degree of freedom. Since our test statistics is less than the critical value of t, so which means our test statistics will lie in the rejection region and we have sufficient evidence to reject null hypothesis.

Therefore, we conclude that the true average lifetime is smaller than what is advertised and so consumer will not purchase the light bulbs.

(b) Now, at 1% significance level, t table gives critical value of -2.405 at 49 degree of freedom. Since our test statistics is higher than the critical value of t, so which means our test statistics will not lie in the rejection region and we have insufficient evidence to reject null hypothesis.

Therefore, we conclude that the true average lifetime is same as what it has been advertised and so consumer will purchase the light bulbs.

6 0

3 years ago