Ask question

Ask question

All categories

2 years ago

13

An epidemiologic survey of roller-skating injuries in Metroville, a city with a population of 100,000 (during the midpoint of th

e year), produced the following data for a particular year:
Number of skaters in Metroville during any given month 12,000
Roller-skating injuries in Metroville 600
Total number of residents injured from roller-skating 1,800
Total number of deaths from roller-skating 90
Total number of deaths from all causes 900

The proportional mortality ratio (%) due to roller-skating was:

a. 90/600 × 100
b. 90/100,000 × 100
c. 90/1,800 × 100
d. 90/900 × 100

1 answer:

Ahat [919]2 years ago

8 0

Answer: c. $\dfrac{90}{1800}\times100\%$

Step-by-step explanation:

As per given , we have

Total number of residents injured from roller-skating =1,800

Total number of deaths from roller-skating = 90

Formula for Mortality rate : $Mortaility\ rate= \dfrac{Deaths\ due \ to\ injury}{Tota\ injuries}$

Then, the proportional mortality ratio (%) due to roller-skating was

= $\dfrac{90}{1800}\times100\%$

= 5%

Hence, the correct answer is c. $\dfrac{90}{1800}\times100\%$

You might be interested in

We're testing the hypothesis that the average boy walks at 18 months of age (H0: p = 18). We assume that the ages at which boys

marusya05 [52]

Answer:

II. This finding is significant for a two-tailed test at .01.

III. This finding is significant for a one-tailed test at .01.

d. II and III only

Step-by-step explanation:

1) Data given and notation

$\bar X=19.2$ represent the battery life sample mean

$\sigma=2.5$ represent the population standard deviation

$n=25$ sample size

$\mu_o =18$ represent the value that we want to test

$\alpha$ represent the significance level for the hypothesis test.

t would represent the statistic (variable of interest)

$p_v$ represent the p value for the test (variable of interest)

2) State the null and alternative hypotheses.

We need to conduct a hypothesis in order to check if the mean battery life is equal to 18 or not for parta I and II:

Null hypothesis: $\mu = 18$

Alternative hypothesis: $\mu \neq 18$

And for part III we have a one tailed test with the following hypothesis:

Null hypothesis: $\mu \leq 18$

Alternative hypothesis: $\mu > 18$

Since we know the population deviation, is better apply a z test to compare the actual mean to the reference value, and the statistic is given by:

$z=\frac{\bar X-\mu_o}{\frac{\sigma}{\sqrt{n}}}$ (1)

z-test: "Is used to compare group means. Is one of the most common tests and is used to determine if the mean is (higher, less or not equal) to an specified value".

3) Calculate the statistic

We can replace in formula (1) the info given like this:

$z=\frac{19.2-18}{\frac{2.5}{\sqrt{25}}}=2.4$

4) P-value

First we need to calculate the degrees of freedom given by:

$df=n-1=25-1=24$

Since is a two tailed test for parts I and II, the p value would be:

$p_v =2*P(t_{(24)}>2.4)=0.0245$

And for part III since we have a one right tailed test the p value is:

$p_v =P(t_{(24)}>2.4)=0.0122$

5) Conclusion

I. This finding is significant for a two-tailed test at .05.

Since the $p_v$ . We reject the null hypothesis so we don't have a significant result. FALSE

II. This finding is significant for a two-tailed test at .01.

Since the $p_v >\alpha$ . We FAIL to reject the null hypothesis so we have a significant result. TRUE.

III. This finding is significant for a one-tailed test at .01.

Since the $p_v >\alpha$ . We FAIL to reject the null hypothesis so we have a significant result. TRUE.

So then the correct options is:

d. II and III only

6 0

2 years ago

At 7:00 AM there were 14,000 gallons of water in Lance’s pool when he noticed there was a leak. After 6 hours there were only 5,

Irina-Kira [14]

Hopefully you can read and learn from this.

4 0

2 years ago

Read 2 more answers

the population of Ketcham high school has been decreasing by 5 % per year.if it's population is currently 2600 which of the foll

kap26 [50]

5% = .05
2600 x .05 = 130
130 x 2 = 260
2600 - 260 = 2340

The population will be 2340 people.

6 0

2 years ago

If 20a-16=12(3-a), then a=?<br><br>a)5/8<br>b)13/8<br>c)21/16<br>d)5/2

lorasvet [3.4K]

ANSWER: B. 13/8

STEP BY STEP THING:

20a−16=12(3−a)

20a−16=−12a+36

32a−16=36

32a=52

32a/32 = 52/32

a = 13/8

5 0

2 years ago

Read 2 more answers

According to the rational root theorem, which number is a potential root of f(x) = 9x8 9x6 – 12x 7?

yaroslaw [1]

The options of the problem are

$A. 0\ B. \frac{1}{7}\ C. 2\ D. \frac{7}{3}$

we have

$9x^{8} +9x^{6} - 12x +7$

we know that

<u>The Rational Root Theorem </u>states that when a root 'x' is written as a fraction in lowest terms

$x=\frac{p}{q}$

p is an integer factor of <u>the constant term</u>, and q is an integer factor of <u>the coefficient of the first monomial</u>.

So

in this problem

the constant term is equal to $7$

and the first monomial is equal to $9x^{8}$ -----> coefficient is $9$

therefore

<u>the answer is the option </u>

D. $\frac{7}{3}$

7 0

2 years ago

Read 2 more answers