The measure of an angle is 3/4 of 60 degrees. What is the measure of the complementary angle?

The mean life of a particular brand of light bulb is 1200 hours. if you know that at about 95% of this brand of bulbs will last

Snowcat [4.5K]

<span>204
First, lookup a standard normal table and see what the z-score is for 0.025 (one half of 100% - 95%) to allow for equal sized tails. You should find that the z-score is 1.96. That means that 95% of the time, the value should be within 1.96 standard deviations of the mean. Now let's calculate the standard deviation. 800 is 800 - 1200 = -400 to the left of the mean of 1200. 1600 is 1600 - 1200 = 400 to the right of the mean of 1200. So we are an equal distance of 400 on both sides of the mean. And we know from the z-score of 1.96, that we're 1.96 standard deviations from the mean. So a little division will give us the standard deviation. Which is: 400 / 1.96 = 204.0816327
So the standard deviation of the light bulbs is 204</span>

4 0

3 years ago

Lisa spends 1/5 of an hour doing her math homework and 1/3 of an hour doing her social studies homework. What fraction of an hou

Sveta_85 [38]

To solve this, all you have to do is add 1/5 and 1/3.
Well, you might be thinking, "But the denominators are not the same! Fractions have to have like denominators in order to be added together!" And you are right. So, all we have to do, is make them both have the same denominator. To do this, we have to multiply both the numerator and denominator by the same number to find an equivalent fraction.
For 1/5, we can multiply both the numerator and denominator by 3, to get 3/15.
Likewise, we can multiply both the numerator and denominator of 1/3 by 5, to get 5/15.
Now, you can easily add 3/15 and 5/15 because all you have to do is add the numerators, because the denominators are the same!
3/15+5/15=8/15, so she spends 8/15 hour on her math and social studies homework.
Hope I helped!

3 0

2 years ago

Tom planted 1/2 of an 8-ft by 9-ft garden with vegetables. He planted tomatoes in 1/3 of the vegetable garden and corn in the re

ser-zykov [4K]

Answer:

Corn was planted in 24 sq.ft. of the vegetable garden.

Step-by-step explanation:

Length of garden = 9 ft

width of garden = 8 ft

Hence we will first find the total area of garden.

Total area of garden = length × width = $8 \times 9 = 72ft^2$

He planted 1/2 of the garden with vegetables.

Hence.

Area of Vegetables garden = $\frac{1}{2}\times \textrm{Total Area of Garden} = \frac{1}{2}\times 72 = 36ft^2$

He planted tomatoes in 1/3 of the vegetable garden and corn in the rest

Area in which tomatoes was planted = $\frac{1}{3}\times \textrm{Area of Vegetables Garden} = \frac{1}{3}\times 36 = 12ft^2$

Hence Area in which corn were planted = Area of Vegetables garden - Area in which tomatoes was planted = $36ft^2-12ft^2=24ft^2$

Hence Area of vegetable garden in which corn was planted is 24 sq.ft.

7 0

2 years ago

Suppose a local manufacturing company claims their production line has a variance of less than 9.0. A quality control engineer d

Alexxx [7]

Answer:

$\chi^2 =\frac{35-1}{9} 2.12^2 =16.979$

$p_v =P(\chi^2$

If we compare the p value and the significance level provided we see that $p_v$ so on this case we have enough evidence in order to reject the null hypothesis at the significance level provided. And that means that the population variance is significantly lower than 9

Step-by-step explanation:

Notation and previous concepts

A chi-square test is "used to test if the variance of a population is equal to a specified value. This test can be either a two-sided test or a one-sided test. The two-sided version tests against the alternative that the true variance is either less than or greater than the specified value"

$n=35$ represent the sample size

$\alpha=0.01$ represent the confidence level

$s =2.12$ represent the sample deviation obtained

$\sigma_0 =3$ represent the value that we want to test

Null and alternative hypothesis

On this case we want to check if the population variance specification is lower than 9 and the deviation lower than 3, so the system of hypothesis would be:

Null Hypothesis: $\sigma^2 \geq 9$

Alternative hypothesis: $\sigma^2$

Calculate the statistic

For this test we can use the following statistic:

$\chi^2 =\frac{n-1}{\sigma^2_0} s^2$

And this statistic is distributed chi square with n-1 degrees of freedom. We have eveything to replace.

$\chi^2 =\frac{35-1}{9} 2.12^2 =16.979$

Calculate the p value

In order to calculate the p value we need to have in count the degrees of freedom , on this case df= n-1= 35-1=34. And since is a left tailed test the p value would be given by:

$p_v =P(\chi^2$

In order to find the p value we can use the following code in excel:

"=CHISQ.DIST(16.979,34,TRUE)"

Conclusion

If we compare the p value and the significance level provided we see that $p_v$ so on this case we have enough evidence in order to reject the null hypothesis at the significance level provided. And that means that the population variance is significantly lower than 9

6 0

3 years ago

What is the y-intercept of y = 1 + 6x?

Tcecarenko [31]

Answer:

Hey!

Your answer is 1 (the y-intercept is 1)

Step-by-step explanation:

x-intercept = ( − 1/ 6 , 0 )

y-intercept = ( 0 , 1 )

Explanation:

Slope formula is

= r i s e/ r u n

Since 6 is obviously 6/ 1 then...

we know that the slope goes up 6 units

and right 1 unit on a graph.

Next we have to find the y-intercept of the line

of y=6x+1, you substitute x as x=0.

y = 6

x + 1

y = 6 ( 0 ) + 1

so then y = 1

HOPE THIS HELPS!!

8 0

2 years ago

Read 2 more answers