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Ipatiy [6.2K]
3 years ago
8

a police officer records the speeds of vehicles on a road.what percent of the vehicles were traveling between 51-55 miles per ho

ur?show work​

Mathematics
1 answer:
Marrrta [24]3 years ago
4 0

Answer:

24%

Step-by-step explanation:

50 is the 100%

so

12/50= 24%

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The diameter of steel rods manufactured on two different extrusion machines is being investigated. Two random samples of sizes
devlian [24]

Answer:

(a) There is no evidence to support the claim that the two machines produce rods with different mean diameters.

P-value is 0.818

(b) 95% confidence interval for the difference in mean rod diameter is (-0.17, 0.27).

This interval shows that the difference in mean is between -0.17 and 0.27.

Step-by-step explanation:

(a) Null hypothesis: The two machines produce rods with the same mean diameter.

Alternate hypothesis: The two machines produce rods with different mean diameter.

Machine 1

mean = 8.73

variance = 0.35

n1 = 15

Machine 2

mean = 8.68

variance = 0.4

n2 = 17

pooled variance = [(15-1)0.35 + (17-1)0.4] ÷ (15+17-2) = 11.3 ÷ 30 = 0.38

Test statistic (t) = (8.73 - 8.68) ÷ sqrt[0.38(1/15 + 1/17)] = 0.05 ÷ 0.218 = 0.23

degree of freedom = n1+n2-2 = 15+17-2 = 30

Significance level = 0.05 = 5%

Critical values corresponding to 30 degrees of freedom and 5% significance level are -2.042 and 2.042.

Conclusion:

Fail to reject the null hypothesis because the test statistic 0.23 falls within the region bounded by the critical values -2.042 and 2.042.

There is no evidence to support the claim that the two machines produce rods with different mean diameters.

Cumulative area of test statistic is 0.5910

The test is a two-tailed test.

P-value = 2(1 - 0.5910) = 2×0.409 = 0.818

(b) Difference in mean = 8.73 - 8.68 = 0.05

pooled sd = sqrt(pooled variance) = sqrt(0.38) = 0.62

Critical value (t) = 2.042

E = t×pooled sd/√n1+n2 = 2.042×0.62/√15+17 = 0.22

Lower limit of difference in mean = 0.05 - 0.22 = -0.17

Upper limit of difference in mean = 0.05 + 0.22 = 0.27

95% confidence interval for the difference in mean rod diameter is between a lower limit of -0.17 and an upper limit of 0.27.

3 0
3 years ago
A, 5+x = 17
Vlad [161]

A. 5+x=17, x = 17-5=12

B. x = 4 x 2.5 = 10

C. x = 27+12 = 39

D. x = 16:4 = 4

E. x = 9 : 3/4 = 12

Answer A and E

3 0
2 years ago
Read 2 more answers
a bag contains 4 red, 3 orange and 5 purple marbles. what is the probability of drawing 2 purple marbles in a row without replac
dlinn [17]

Step-by-step explanation: this one is for zack!!!!!!!!!

5 0
3 years ago
Read 2 more answers
Anyone know the answer
Arlecino [84]

Answer: A: 2


Step-by-step explanation:

In order to find the slope of the line, you must know about rise/run, which means that you go up and over to your next point. For example: I started at the point 0,-4 and went up two and to the right one to the point -2,1, which i rose 2 and ran 1, or 2/1, which equals 2

3 0
3 years ago
The grades on a language midterm at Santa Rita are roughly symmetric with u = 77 and o = 3.5.
labwork [276]

Answer:.86

Step-by-step explanation:

Put the given data within the formula for the zscore.

6 0
3 years ago
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