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marishachu [46]
3 years ago
13

a researcher wants to know the typing speed of the students in a large vocational school. the population standard deviation is p

reviously known to be 2.5 minutes. if the researcher wants a margin of error of 0.50 minute and an alpha level of 0.05, what should be the sample size?
Mathematics
1 answer:
tester [92]3 years ago
4 0
1) It is known that a laboratory task takes the average person 2.5 seconds. A researcher was interested in whether older people are slower (take longer) on this task. The researcher tested 30 randomly selected 80-year-olds. Their mean time was 2.7 seconds, with an estimated population standard deviation of 1.4 seconds. What should the researcher conclude (use the .05 level)? a. /2 Identify the populations involved: population 1 = _____________________________________________________________________ population 2 = _____________________________________________________________________ b. /2 State the research and null hypothesis: Research Hypothesis = _____________________________________________________________ Null Hypothesis = _________________________________________________________________ c. /6 Determine the characteristics of the comparison distribution (hint: it is a distribution of means): mean of the distribution of means = degrees of freedom = estimated population variance = estimated population standard deviation = variance of the distribution of means = standard deviation of distribution of means = d. /1 Cutoff sample score on the comparison distribution at which we’ll reject H0 (hint: 1 or 2 tails?) = e. /1 Determine your sample’s score on the comparison distribution = f. /1 Accept or reject the null hypothesis? g. /4 Sketch the distributions involved:
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Eight children were in a ballet class. Three of them were wearing a pink leotard. What fraction of them did not have a pink leot
leva [86]

Answer:

5/8

Step-by-step explanation:

8 children in class

3 have pink on

8-3 = 5

That means 5 do not have pink

Fraction that do not have pink

those that do not have pink/total

5/8

5 0
3 years ago
In this question, all lengths are in centimetres.
JulsSmile [24]

Answer:

Step-by-step explanation:

AB/AC =1/2

(3x-4)/(2x+12)=1/2

2(3x-4) = 1(2x+12)

6x-8=2x+12

4x=20

X=5

AC/BC =3x-4/7x-2=22/33=2/3

AB/AC=3x-4/7x-2=22/33=2/3

AB/AC=3x-4/2x+12

6x-8=2x+12

You would get 4/5 still trying to work out the last mark

3 0
3 years ago
Does anyone know how to solve this?
Bezzdna [24]

Use this version of the Law of Cosines to find side b:

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We want side b.

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After finding b, you can use the Law of Sines to find angles A and C or use other forms of the Law of Cosines to find angles A and C.

Try it....

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Each flower arrangement will have 5 lillies and 13 roses
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3 years ago
Read 2 more answers
Prove the theorem (AB )^T= B^T. A^T
Lisa [10]

Answer:

(AB)^T = B^T.A^T  (Proved)

Step-by-step explanation:

Given  (AB )^T= B^T. A^T;

To prove this expression, we need to apply multiplication law, power law and division law of indices respectively, as shown below.

(AB)^T = B^T.A^T\\\\Start, from \ Right \ hand \ side\\\\B^T.A^T = \frac{B^T.A^T}{A^T}.\frac{B^T.A^T}{B^T} (multiply \ through) \\\\                = \frac{A^{2T}.B^{2T}}{A^T.B^T} \\\\=\frac{(AB)^{2T}}{(AB)^T} \ \ (factor \ out \ the power)\\\\= (AB)^{2T-T}  \ (apply \ division \ law \ of \ indices; \ \frac{x^a}{x^b} = x^{a-b})\\\\= (AB)^T \ (Proved)

3 0
3 years ago
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