3. 24% of weight of an explosive mixture is saltpetre. Find the weight of a sample in which the other ingredients

Mathematics

1 answer:

Art [367]2 years ago

5 0

Answer:

76% of X= 9.12. X= 12 gram. Therefore weight of the sample is 12 gram.

Step-by-step explanation:

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Isa and Jack have part-time jobs.

enot [183]

By process of elimination and plugging in the math we can say that Jack earns 8.25 an hour by multiplying 2*8.25=16.50. Isa must then earn 9.50, therefore she earns a greater hourly pay then Jack as a result

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2 years ago

If a hurricane was headed your way, would you evacuate? The headline of a press release states, "Thirty-four Percent of People o

IgorC [24]

Answer:

The 98% confidence interval would be given by (0.326;0.354)

Step-by-step explanation:

1) Notation and definitions

$X=63$ number of people who live within 20 miles of the coast in high hurricane risk counties of eight southern states

$n=6138$ random sample taken

$\hat p=0.34$ estimated proportion of people who live within 20 miles of the coast in high hurricane risk counties of eight southern states

$p$ true population proportion of people who live within 20 miles of the coast in high hurricane risk counties of eight southern states

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

The population proportion have the following distribution

$p \sim N(p,\sqrt{\frac{p(1-p)}{n}})$

2) Confidence interval

In order to find the critical value we need to take in count that we are finding the interval for a proportion, so on this case we need to use the z distribution. Since our interval is at 98% of confidence, our significance level would be given by $\alpha=1-0.98=0.02$ and $\alpha/2 =0.01$ . And the critical value would be given by: