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Elina [12.6K]
3 years ago
9

Step by step solve 18×20, I find double 18 and then multiply by 10

Mathematics
1 answer:
Arturiano [62]3 years ago
3 0
18x20 is 360
18x10 is 180
18x10 again is 180
180+180=360
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In how many ways we can test wether ratios from a proportion ?
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From what I learnt so far, there are 3 possible ways of finding whether ratios form a proportion
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A new post-surgical treatment is being compared with a standard treatment. Seven subjects receive the new treatment, while seven
AnnyKZ [126]

Answer:

t=\frac{17.71-28.71}{\sqrt{\frac{4.461^2}{7}+\frac{7.387^2}{7}}}}=-3.372  

df=n_{S}+n_{N}-2=7+7-2=12

Since is a one sided test the p value would be:

p_v =P(t_{(12)}

If we compare the p value and the significance level given \alpha=0.05 we see that p_v so we can conclude that we have enough evidence to reject the null hypothesis, so we can conclude that the mean time for the new treatment is significantly lower than the time for the standard treatment at 5% of significance.

Step-by-step explanation:

New: 12, 13,15,19,20,21

Standard: 18,23,24,30,32,35

We can calculate the sample mean and deviation with the following formulas:

\bar X = \frac{\sum_{i=1}^n X_i}{n}

s= \sqrt{\frac{\sum_{i=1}^n (X_i -\bar X)^2}{n-1}}

Data given and notation

\bar X_{N}=17.71 represent the mean for the new case

\bar X_{S}=28.71 represent the mean for the standard case

s_{N}=4.461 represent the sample standard deviation for the new case

s_{S}=7.387 represent the sample standard deviation for the standard case

n_{S}=7 sample size selected for the standard case

n_{N}=7 sample size selected for the new case

\alpha=0.05 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)

State the null and alternative hypotheses.

We need to conduct a hypothesis in order to check if recovery time for patients who receive the new treatment is less than the mean for patients who receive the standard treatment, the system of hypothesis would be:

Null hypothesis:\mu_{N} \geq \mu_{S}

Alternative hypothesis:\mu_{N} < \mu_{S}

If we analyze the size for the samples both are less than 30 so for this case is better apply a t test to compare means, and the statistic is given by:

t=\frac{\bar X_{N}-\bar X_{S}}{\sqrt{\frac{s^2_{N}}{n_{N}}+\frac{s^2_{S}}{n_{S}}}} (1)

t-test: "Is used to compare group means. Is one of the most common tests and is used to determine whether the means of two groups are equal to each other".

Calculate the statistic

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

t=\frac{17.71-28.71}{\sqrt{\frac{4.461^2}{7}+\frac{7.387^2}{7}}}}=-3.372  

P-value

The first step is calculate the degrees of freedom, on this case:

df=n_{S}+n_{N}-2=7+7-2=12

Since is a one sided test the p value would be:

p_v =P(t_{(12)}

Conclusion

If we compare the p value and the significance level given \alpha=0.05 we see that p_v so we can conclude that we have enough evidence to reject the null hypothesis, so we can conclude that the mean time for the new treatment is significantly lower than the time for the standard treatment at 5% of significance.

6 0
4 years ago
If I put 4736 marbles into groups of 100, how many groups would I have? Show how you figured it out.
NNADVOKAT [17]
Divide to find out

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Therefore, we have  to round, and then we get 47. 

Answer: 47 groups and a remainder of 36. 
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Afina-wow [57]

Answer:

2346

Step-by-step explanation:D

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3 years ago
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