Math! 10 points! 7th grade work! Please help :) 3-6

Can you solve 2x + 17 = 29 by first dividing and then subtracting? Do you get the same answer if you subtract first and then div

nikdorinn [45]

Answer:

You cannot divide first because in equations you need to isolate the variable, which means subtracting first. The outcome will be different if you change the order.

8 0

3 years ago

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A company surveyed 2400 men where 1248 of the men identified themselves as the primary grocery shopper in their household. a) E

polet [3.4K]

Answer:

a) With a confidence level of 98%, the percentage of all males who identify themselves as the primary grocery shopper are between 0.4962 and 0.5438.

b) The lower limit of the confidence interval is higher that 0.43, so if he conduct a hypothesis test, he will find that the data shows evidence to said that the fraction is higher than 43%.

c) $\alpha =1-0.98=0.02$

Step-by-step explanation:

If np' and n(1-p') are higher than 5, a confidence interval for the proportion is calculated as:

$p'-z_{\alpha/2}\sqrt{\frac{p'(1-p')}{n} }\leq p\leq p'+z_{\alpha/2}\sqrt{\frac{p'(1-p')}{n} }$

Where p' is the proportion of the sample, n is the size of the sample, p is the proportion of the population and $z_{\alpha/2}$ is the z-value that let a probability of $\alpha/2$ on the right tail.

Then, a 98% confidence interval for the percentage of all males who identify themselves as the primary grocery shopper can be calculated replacing p' by 0.52, n by 2400, $\alpha$ by 0.02 and $z_{\alpha/2}$ by 2.33

Where p' and $\alpha$ are calculated as:

$p' = \frac{1248}{2400}=0.52\\\alpha =1-0.98=0.02$

So, replacing the values we get:

$0.52-2.33\sqrt{\frac{0.52(1-0.52)}{2400} }\leq p\leq 0.52+2.33\sqrt{\frac{0.52(1-0.52)}{2400} }\\0.52-0.0238\leq p\leq 0.52+0.0238\\0.4962\leq p\leq 0.5438$

With a confidence level of 98%, the percentage of all males who identify themselves as the primary grocery shopper are between 0.4962 and 0.5438.

The lower limit of the confidence interval is higher that 0.43, so if he conduct a hypothesis test, he will find that the data shows evidence to said that the fraction is higher than 43%.

Finally, the level of significance is the probability to reject the null hypothesis given that the null hypothesis is true. It is also the complement of the level of confidence. So, if we create a 98% confidence interval, the level of confidence $1-\alpha$ is equal to 98%

It means the the level of significance $\alpha$ is:

$\alpha =1-0.98=0.02$

4 0

3 years ago

On a blueprint, the scale indicates that 4 centimeters

makvit [3.9K]

Answer:

Length: 15 feet Width: 105 feet

Step-by-step explanation:

set up a proportion of x over 4 and x over 12 fill in the length or width that you do know. Then cross multiply and solve the simple equation you get: for example) 60 = 4x. Just divide both sides by 4 to get x by itself.

Hope this answered your question!

6 0

3 years ago

Convert -3x + 2y = 10 into slope-intercept form.

GrogVix [38]

Y=3/2x+5 is the answer

4 0

3 years ago

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I need help answering all of these. My teacher thinks that we should know this even though he hasn´t taught us any of this. plea

bearhunter [10]

Answer:

Step-by-step explanation:

x/2=3.5

x=3.5*2

x=7

3 0

3 years ago