Whole numbers between 200 and 220 that are multiple of 3

An electrician charged a fee of $45 plus $60 per hour to come to Ed's house and make a repair. How many hours did the repair tak

viva [34]

Answer:

1 hour and 15 minutes

Step-by-step explanation:

$120 - $45 = $75

$75 ÷ $60 = 1.25 hours or and 1 hour and 15 minutes

5 0

2 years ago

In a study, researchers wanted to measure the effect of alcohol on the hippocampal region, the portion of the brain responsibl

ziro4ka [17]

Answer:

The hippocampus volumes in the alcoholic adolescents are less than the normal volume of 9.02 cm³

Step-by-step explanation:

Let x= the hippocampus volumes in the alcoholic adolescents

We'll conduct a hypothesis test at the 0.01 significance level with

Null hypothesis: x = 9.02 cm³

Alternate hypothesis: x < 9.02 cm³

A sample of 13 alcoholic adolescents gives the parameters

size=N= 13

mean=M= 8.12 cm³

standard deviation= s= 0.8 cm³

According to the sample, with 99% confidence, t statistic for the value X=9.02 can be found using the formula:

t= $\frac{X-M}{\frac{s}{\sqrt{N} } }$ where

M is the sample mean (8.12)
s is the standard deviation of the sample (0.8)
N is the sample size (13)

If we put these numbers in the formula:

t= $\frac{9.02-8.12}{\frac{0.8}{\sqrt{13} } }$ =4.056

One tailed critical value for the sample with 12 degrees of freedom (sample size-1) in 99% confidence level is 2.681.

Since t value (4.056) is bigger than the critical value, we fail to reject the alternate hypothesis, therefore reject the null hypothesis and accept alternate hypothesis.

5 0

2 years ago

A fly starts out 2 meters from a lightbulb, flies closer to the light, then farther away (2 meters again). At this point the fly

Lorico [155]

Answer

f(t)=2cos(t)

Step-by-step explanation:

let's describe the situation first, a fly is starting 2 meters from the bulb and flies towards the bulb and when it is really close to the bulb, it flies 2 meters further away from the bulb this means that it reaches d = 0m (distance from the bulb) and then flies further 2 meters so d = -2m.

it this point the fly returns back and touches the bulb and flies away (ends it's oscillatory motion ). d = 0 again and story ends here.

here if we want to model this problem with time function , the cosine function seems the best fit with amplitude of 2, so the answer is f(t) = 2cos(t).

Now you can ask why cosine function? well if you look at the graph or the plot of the function it perfectly captures the physical situation going on here in this problem.

Domain is 0 to 2 $\pi$ because it is one complete cycle and the range is -2 to +2.