1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
Oksi-84 [34.3K]
3 years ago
10

If p is a given sample proposition n is the sample size, and a is the number of standard deviations at a confidence level, what

is the standard error of the proportion?
Mathematics
1 answer:
Bas_tet [7]3 years ago
5 0

Answer:

The standard error of a proportion p in a sample of size n is given by: s = \sqrt{\frac{p(1-p)}{n}}

Step-by-step explanation:

Central Limit Theorem

The Central Limit Theorem establishes that, for a normally distributed random variable X, with mean \mu and standard deviation \sigma, the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean \mu and standard deviation s = \frac{\sigma}{\sqrt{n}}.

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

For a proportion p in a sample of size n, the sampling distribution of the sample proportion will be approximately normal with mean \mu = p and standard deviation s = \sqrt{\frac{p(1-p)}{n}}

In this question:

The standard error of a proportion p in a sample of size n is given by: s = \sqrt{\frac{p(1-p)}{n}}

You might be interested in
The burning times of scented candles, in minutes, are normally distributed with a mean of 249 and a standard deviation of 20. Fi
Marysya12 [62]

Answer:

The candle burns for 244 minutes.

Step-by-step explanation:

When the distribution is normal, we use the z-score formula.

In a set with mean \mu and standard deviation \sigma, the zscore of a measure X is given by:

Z = \frac{X - \mu}{\sigma}

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.

In this question, we have that:

\mu = 249, \sigma = 20

Find the number of minutes a scented candle burns if it burns for a shorter time than 60% of all scented candles.

This is the 100-60 = 40th percentile, which is X when Z has a pvalue of 0.4. So X when Z = -0.253.

Z = \frac{X - \mu}{\sigma}

-0.253 = \frac{X - 249}{20}

X - 249 = -0.253*20

X = 244

The candle burns for 244 minutes.

7 0
3 years ago
A map has a scale of 4 inches :25 miles .How far are two cities on a map if they are 120 miles apart?
tensa zangetsu [6.8K]

Answer:

19.2 in

Step-by-step explanation:

Set up a proportion to solve this...

4 inches is to 25 miles as x inches is to 120 miles

4/25 = x/120         now cross multiply to and solve for x

480 = 25x

 480/25 = x

     19.2 = x

5 0
3 years ago
A random sample of 9 wheels of cheese yielded the following weights in pounds has a sample mean of 20.90 and a sample variance o
Ronch [10]

Answer:

2.002 \leq \sigma^2 \leq 11.365

Step-by-step explanation:

1) Data given and notation

s represent the sample standard deviation

s^2 represent the sample variance

n=9 the sample size

Confidence=90% or 0.90

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 mean or variance 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.

The Chi Square distribution is the distribution of the sum of squared standard normal deviates .

2) Calculating the confidence interval

The confidence interval for the population variance is given by the following formula:

\frac{(n-1)s^2}{\chi^2_{\alpha/2}} \leq \sigma \frac{(n-1)s^2}{\chi^2_{1-\alpha/2}}

On this case we need to find the sample standard deviation with the following formula:

s=sqrt{\frac{\sum_{i=1}^9 (x_i -\bar x)^2}{n-1}}
The sample variance given was [tex]s^2=3.45

The next step would be calculate the critical values. First we need to calculate the degrees of freedom given by:

df=n-1=9-1=8

Since the Confidence is 0.90 or 90%, the value of \alpha=0.1 and \alpha/2 =0.05, and we can use excel, a calculator or a table to find the critical values.  

The excel commands would be: "=CHISQ.INV(0.05,8)" "=CHISQ.INV(0.95,8)". so for this case the critical values are:

\chi^2_{\alpha/2}=15.507

\chi^2_{1- \alpha/2}=2.732

And replacing into the formula for the interval we got:

\frac{(9)(3.45)}{15.507} \leq \sigma \frac{(9)(3.45)}{2.732}

2.002 \leq \sigma^2 \leq 11.365

7 0
3 years ago
Brooke saved the same amount of money each week for four weeks. She made this table to show how much money she saved.
Musya8 [376]

Answer:

In 10 weeks of time, Brooke would  earn $ 20.

Step-by-step explanation:

Here, according to the table:

The money saved in week 1   =  $ 2   =   $(1  x 2)

The money saved in week 2  =  $ 4   =  $ ( 2 x 2)

The money saved in week 3   =  $ 6  =  $ ( 3 x 2)

The money saved in week 4   =  $ 8 =   $ ( 4 x 2)

So, by the graph relation, we can see that:

The amount saved in n weeks = ( n x 2) dollars

So, the amount saved by Brooke in 10 weeks is:

Put n =  10, we get:

The money saved  = 2 n = 2 x 10 = $ 20

Hence, in 10 weeks of time, Brooke would  earn $ 20.

5 0
3 years ago
Denise used blocks to model the following situation. How can Denise use her model to find the number of trucks the dealer sells
Ksju [112]

Answer:

you have the same quiestion 3 times

Step-by-step explanation:

3 0
2 years ago
Other questions:
  • Chris has a bag of sweets. there are more than 20 sweets in a bag.
    14·2 answers
  • A man on the deck of a ship is 14 ft above water level. He observes that the angle of elevation of the top of a cliff is 40 degr
    8·1 answer
  • Cherries cost $5.68 a pound. Will $20 be enough to buy a 4.1-pound bag of cherries? Explain how to determine whether $20 is the
    10·2 answers
  • 15 decreased by twice a number
    10·1 answer
  • The Graph shows the function f(x)=2^x what is the value of X when f(x)=8
    8·1 answer
  • Ωωωωωωωωωωωωωωωωω WILL GIVE BRAINLIESTEET<br><br> Given: ∆ABC, AB = 45 AC = CB = 34 Find: m∠B
    8·1 answer
  • A shopper needs 48 hot dogs. The store sells identical hot dogs in 2 differently sized packages. They sell a six-pack of hot dog
    11·2 answers
  • Which number line represents all of the values of x for the equation x2 = 36?
    7·1 answer
  • Please help ill mark brainliest
    13·2 answers
  • Help me with this math question please
    12·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!