Which of the following statements is not true?

The minute hand of a clock is 6 inches long and moves from 12 to 1 o'clock. How far does the tip of the minute hand move? Expr

Strike441 [17]

Answer: 12.57

Step-by-step explanation:

4 0

2 years ago

Determine the sample size needed to construct a 90% confidence interval to estimate the population proportion when p = 0.65 and

WINSTONCH [101]

Answer:

n=170

Step-by-step explanation:

1) Notation and definitions

$n$ random sample taken (variable of interest)

$\hat p=0.65$ estimated proportion.

$p$ true population

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

The population proportion have the following distribution

$p \sim N(p,\sqrt{\frac{\hat p(1-\hat p)}{n}})$

In order to find the critical value we need to take in count that we are finding the interval for a proportion, so on this case we need to use the z distribution. Since our interval is at 90% of confidence, our significance level would be given by $\alpha=1-0.90=0.1$ and $\alpha/2 =0.05$ . And the critical value would be given by:

$z_{\alpha/2}=\pm 1.64$

The margin of error for the proportion interval is given by this formula:

$ME=z_{\alpha/2}\sqrt{\frac{\hat p (1-\hat p)}{n}}$ (a)

And on this case we have that $ME =\pm 0.06$ and we are interested in order to find the value of n, if we solve n from equation (a) we got:

$n=\frac{\hat p (1-\hat p)}{(\frac{ME}{z})^2}$ (b)

And replacing into equation (b) the values from part a we got:

$n=\frac{0.65(1-0.65)}{(\frac{0.06}{1.64})^2}=169.968$

And rounded up we have that n=170

6 0

3 years ago

At 7:00 p.m., there are 1,000 home-team fans and 700 away-team fans at a football game. After 7:00 p.m, 15 home team fans arrive

OleMash [197]

Answer:

Therefore the ratio of home-team fan to away team fan at 8:00 p.m is

=109:67

Step-by-step explanation:

Initially , total home team fans =1000

and away team fans = 700.

7:00 pm to 8:00 pm = 1 hour = 60 minutes

Given that

Every 10 minutes the number of arrival home team fans is 15.

Then in 1 minutes the number of arrival home team fans is $\frac{15}{10}$

and in 60 minutes the number of arrival home team fans is $\frac{15 \times 60}{10}$

=90

Therefore total home team fans = (90+1000)=1090

Given that

Every 10 minutes 5 fans leave of away team leave.

then in 1 minutes $\frac{5}{10}$ fans leave of away team leave.

and In 60 minutes $\frac{5\times 60}{10}$ =30 fans leave of away team leave.

Since 30 away team fans leave.

Total away team fans = (700-30)=670

Therefore the ratio of home-team fan to away team fan at 8:00 p.m is

=1090:670

=109:67

4 0

3 years ago

The number of users on a website has grown exponentially since its launch. After 2 months, there were 90 users. After 4 months,

grigory [225]

Answer:

10(3)^x

Step-by-step explanation:

The function contains the points (2,90) and (4,810). Use the general form y=abx to write two equations:

90=ab^2 and 810=ab^4

Solve each equation for a:

a=90/b^2 and a=810/b^4

Since a=a, set the other sides of the equations equal and solve for b.

90/b2=810/b4

Cross multiply, then divide and simplify as follows:

90b^4=810b^2

b^4/b^2=810/90

b^2=90

b^3

Now, use the value of b and the point (2,90) to find the value of a.

90=a(3^2)

a=10

So, substitute answers in original equation for a final answer of f(x)=10(3)^x.

8 0

3 years ago

Hal forgot the number of people at the basketball game.He does remember that the number had four digits and a 3 in the tens plac

Greeley [361]

There are a lot of numbers you can think of, for example, 1030, or even 9939, but I don't recommend you put that ;)

5 0

3 years ago

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