What is math compass used for ?

Your friend is wrapping 1 meter of twine around a spool with a 2-centimeter diameter. The spool is thin and accommodates only on

Kazeer [188]

Answer:

a) 6 complete times

b) 19.3%

Step-by-step explanation:

In every turn, the diameter of the twine increases 1 cm.

After the first turn, there is a total wrapped of 3.14*2=6.3 cm.

After the second turn, we have wrapped 6.3+3.14*(2+1)=15.7 cm.

If we continue with these algorithm, we have that after the 6th turn we have 84.8 cm wrapped. This is the last complete turn.

T = 0 D = 2 cm. Wrapped = 6.3 cm. Total wrapped = 6.3 cm.

T = 1 D = 3 cm. Wrapped = 9.4 cm. Total wrapped = 15.7 cm.

T = 2 D = 4 cm. Wrapped = 12.6 cm. Total wrapped = 28.3 cm.

T = 3 D = 5 cm. Wrapped = 15.7 cm. Total wrapped = 44 cm.

T = 4 D = 6 cm. Wrapped = 18.8 cm. Total wrapped = 62.8 cm.

T = 5 D = 7 cm. Wrapped = 22.0 cm. Total wrapped = 84.8 cm.

T = 6 D = 8 cm. Wrapped = 25.1 cm. Total wrapped = 110 cm.

There are left (100-84.8) = 15.2 cm to wrap around the twine, which has a 25.1 cm diameter by now.

The perimeter of the twine is 3.14*25.1=78.8 cm.

The percentage of a complete circle that the last wrapping of the twine will make is:

P = 15.2/78.8 = 0.193 = 19.3%

4 0

3 years ago

Let n1equals50, Upper X 1equals30, n2equals50, and Upper X 2equals10. Complete parts (a) and (b) below. a. At the 0.05 leve

Viefleur [7K]

Answer:

Null hypothesis: $p_{1} = p_{2}$

Alternative hypothesis: $p_{1} \neq p_{2}$

$z=\frac{0.6-0.2}{\sqrt{0.4(1-0.4)(\frac{1}{50}+\frac{1}{50})}}=4.082$

$p_v =2*P(Z>4.082)=4.46x10^{-5}$

So the p value is a very low value and using any significance level for example $\alpha=0.05$ always $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis, and we can say the the proportion 1 is significantly different from proportion 2.

Step-by-step explanation:

1) Data given and notation

$X_{1}=30$ represent the number of people with a characteristic in 1

$X_{2}=10$ represent the number of people with a characteristic in 2

$n_{1}=50$ sample of 1 selected

$n_{2}=50$ sample of 2 selected

$p_{1}=\frac{30}{50}=0.6$ represent the proportion of people with a characteristic in 1

$p_{2}=\frac{10}{50}=0.2$ represent the proportion of people with a characteristic in 2

z would represent the statistic (variable of interest)

$p_v$ represent the value for the test (variable of interest)

2) Concepts and formulas to use

We need to conduct a hypothesis in order to check if the proportion 1 is different from proportion 2 , the system of hypothesis would be:

Null hypothesis: $p_{1} = p_{2}$

Alternative hypothesis: $p_{1} \neq p_{2}$

We need to apply a z test to compare proportions, and the statistic is given by:

$z=\frac{p_{1}-p_{2}}{\sqrt{\hat p (1-\hat p)(\frac{1}{n_{1}}+\frac{1}{n_{2}})}}$ (1)

Where $\hat p=\frac{X_{1}+X_{2}}{n_{1}+n_{2}}=\frac{30+10}{50+50}=0.4$

3) Calculate the statistic

Replacing in formula (1) the values obtained we got this:

$z=\frac{0.6-0.2}{\sqrt{0.4(1-0.4)(\frac{1}{50}+\frac{1}{50})}}=4.082$

4) Statistical decision

For this case we don't have a significance level provided $\alpha$ , but we can calculate the p value for this test.

Since is a two sided test the p value would be:

$p_v =2*P(Z>4.082)=4.46x10^{-5}$

So the p value is a very low value and using any significance level for example $\alpha=0.05$ always $p_v$ so we can conclude that we have enough evidence to reject the null hypothesis, and we can say the the proportion 1 is significantly different from proportion 2.

3 0

3 years ago

Round the number to the place of the underlined digit. 4.327 (The underlined Digit is 3)

Genrish500 [490]

Answer:4.3

You round to the tenths place

5 0

2 years ago

DIVIDE. Show how you used partial quotients to find your answer. 1,562 ÷ 34

Temka [501]

1562 divided by 35= 45 with a remainder of 32

6 0

3 years ago

Matthew worked a summer job and saved $900 each

Dmitry_Shevchenko [17]

Answer:

1400

Step-by-step explanation:

hope that helps <3

5 0

2 years ago