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Tcecarenko [31]
3 years ago
7

An article in Cancer Research [“Analyses of Litter-Matched Time-to-Response Data, with Modifications for Recovery of Interlitter

Information” (1977, Vol. 37, pp. 3863–3868)] tested the tumorigenesis of a drug. Rats were randomly selected from litters and given the drug. The times of tumor appearance were recorded as follows: 101, 104, 104, 77, 89, 88, 104, 96, 82, 70, 89, 91, 39, 103, 93, 85, 104, 104, 81, 67, 104, 104, 104, 87, 104, 89, 78, 104, 86, 76, 103, 102, 80, 45, 94, 104, 104, 76, 80, 72, 73 Calculate a 95% confidence interval on the standard deviation of time until a tumor appearance. Check the assumption of normality of the population and comment on the assumptions for the confidence interval

Mathematics
1 answer:
Fudgin [204]3 years ago
5 0

Answer:

2.51 < σ < 3.92

Step-by-step explanation:

We will use Chi-Square distribution to create the interval.  We have the following information:

n = 41

Level of Confidence : 95%,

This corresponds to Chi-Square values of:

24.433 for the left tail and 59.342 for the right tail

We need to calculate the sample Variance.  This is done on attached photo 1 (the shortcut formula for finding variance was used)

We get s = 9.3866.

See the construction of the confidence interval on the second attached photo

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3 years ago
When you add 18 to 1/4 of a number. I dont need to solve it but i need to make it an equation. x equals a number. so would the a
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Yes, that answer is right, good job.
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A ski area has a high-speed lift that can move 2,400 skiers to the top of the mountain each hour. Write an expression describing
mihalych1998 [28]

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2,400h

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7 0
2 years ago
Maria made 171 for 9 hours of work. at the same rate, how much would she make for 7 hours of work
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4 0
3 years ago
Read 2 more answers
Three years ago Alicia was twice as old as her brother Carlos. In two more years Alicia will be just 50% older than Carlos. How
likoan [24]

Answer:

<h3>13 years</h3>

Step-by-step explanation:

Let the present age of Alicia be x

Let the present age of her brother be y

Three years ago;

Alicia age = x - 3

Her brother's age = y - 3

If three years ago Alicia was twice as old as her brother Carlos, then;

X - 3 = 2(Y-3)

x-3 = 2y - 6

x = 2y - 3 ...1

In two years time;

Alicias age = x+2

Her brother's age = y +2

If in two more years Alicia will be just 50% older than Carlos, then;

x+2 = y + 2 + (0.5(y+2))

x+2 = y+2 + 0.5y + 1

x+2 = 1.5y+3

x = 1.5y + 1 ...2

Equating 1 and 2;

2y - 3 = 1.5y + 1

2y - 1.5y = 1+3

0.5y = 4

y = 4/0.5

y = 8

Since x = 2y-3

x = 2(8) - 3

x = 16-3

x = 13

Hence Alicia will be 13 years old today

7 0
3 years ago
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