What is 2/5% as an equivalent fraction?

A market surveyor wishes to know how many energy drinks teenagers drink each week. They want to construct a 85% confidence inter

Gre4nikov [31]

Answer:

$7.3-1.440\frac{1.2}{\sqrt{830}}=7.240$

$7.3+1.440\frac{1.2}{\sqrt{830}}=7.360$

So on this case the 85% confidence interval would be given by (7.2;7.4)

Step-by-step explanation:

Previous concepts

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".

$\bar X=7.3$ represent the sample mean

$\mu$ population mean (variable of interest)

$\sigma =1.2$ represent the population standard deviation

n=830 represent the sample size

Solution to the problem

The confidence interval for the mean is given by the following formula:

$\bar X \pm t_{\alpha/2}\frac{s}{\sqrt{n}}$ (1)

Since the Confidence is 0.85 or 85%, the value of $\alpha=0.15$ and $\alpha/2 =0.075$ , and we can use excel, a calculator or a table to find the critical value. The excel command would be: "=-NORM.INV(0.075,0,1)".And we see that $z_{\alpha/2}=1.440$

Now we have everything in order to replace into formula (1):

$7.3-1.440\frac{1.2}{\sqrt{830}}=7.240$

$7.3+1.440\frac{1.2}{\sqrt{830}}=7.360$

So on this case the 85% confidence interval would be given by (7.2;7.4)

7 0

3 years ago

An elementary school is offering 3 language classes: one in Spanish, one in French, and one in German. These classes are open to

Firlakuza [10]

Answer:

0.3689 ; 0.3592 ; 0.6301

Step-by-step explanation:

Spanish = S

French = F

German = G

n(S) = 37 ; n(F) = 38 ; n(G) = 21

n(SnF) = 17 ; n(SnG) = 7 ; n(FnG) = 10

n(SnFnG) = 3

n(SnF) only = 17 - 3 = 14 ;

n(SnG) only = 7 - 3 = 4 ;

n(FnG) only = 10 - 3 = 7

n(S) only = 37 - (14 + 3 + 4) = 16 ;

n(F) only = 38 - (14 + 3 + 7) = 14;

n(G) only = 21 - (7 + 3 + 4) = 7

Probability of not being in any language class :

Number of students not in any class (x)

(16+7+14+14+4+7+3+x) = 103

65 + x = 103

x = 103 - 65

x = 38

Probability, P = required outcome / Total possible outcomes

P(not in any class) = 38 / 103

= 0.3689

2.) probability of taking exactly one class :

Either Spanish or German or French

16/103 + 7/103 + 14/103 = 37/103 = 0.3592

3.) probability that atleast one of two students is taking a language class :

Probability that a student chosen is taking a language class :

Number of students taking a language class / total number of students

= 65 / 103

= 0.631

[P(takes class) * p(does not take class)] + [p(takes class) * p(takes class)]

(0.631 * 0.3689) + (0.631 * 0.631) = 0.6301

7 0

3 years ago

If P(E)=.14 what is P(E')

AveGali [126]

<span>By complement rules, P(E') + P(E) = 1

So 1 - P(E) = </span>P(E')<span> = 1 - 0.14 = 0.86

Final answer: </span>P(E') = 0.86

7 0

4 years ago

5 pennies+ 6 nickles+8 dimes+2 quarters

Wewaii [24]

Answer:

165

Step-by-step explanation:

5 + 30 + 80 + 50 = 165

6 0

3 years ago

Read 2 more answers

I just need someone to talk to plz

7nadin3 [17]

Any problem? u can talk:)

7 0

3 years ago