two population means
at a recent faculty meeting, we were wondering if freshmen have more free time than seniors. we took a sample of 25 freshmen and 23 seniors. each student was asked to record the amount of free time he or she had in a typical week. the mean for the freshmen was found to be 29 hours of free time per week with a standard deviation of 7.0 hours. for the seniors, the mean was 22 hours of free time per week with a standard deviation of 6.2 hours. assume that the two populations are normally distributed with equal but unknown population standard deviations. test at a 5% significance level whether the two-population means are different.

if this problem calls for:
use test statistic
use degrees of freedom


pooled variance test
3.897
calculate your own


separate variance test
3.655
46


paired samples test
2.546
calculate your own


chi-squared test
calculate your own
calculate your own
this is a two sample t testho: muf - mus = 0ha: muf - mus not equal to 0muf - mus = actual difference in the means of hours per week of free time for freshman minus seniorsassuming two random samples, normality and independence, reject ho if the calculated t > critical tt calculated = (29-22)/sqrt((7^2/25)+(6.2^2/23)) = 3.67t critical = t (df=46 alpha=0.025 two tailed)= 2.013t calculated > t critical, reject ho. there is evidence that the two means are different
histogram  divide data o equal width o no overlapping  bar chart o skew­ pulls direction of mean o symmetric numeric summary center, spread, and location  greek letters for population  roman letters for statistics 1. mean  µ= population mean  x bar= sanple mean o ∑ xi  all over n= sample mean  k=0 2. mean vs. median a. mean used the most b. n is small when outliers occur c. use median, mean is too affected spread 1. range (max­min) a. sensitive to outliers 2. iqr a. not sensitive to outliers variability­ xi­x bar a)
\(x^{2}-GOF\)
  

We are comparing observed values to expected values
  

b) Another test must be used Cholesterol level is quantitative and not a count.
  

c) \(x^{2}\) test for independence
Relation between political leaning and choice of major nba) but the halves vs quarters are because the full game length is shorter in college than in nba, so quarters would be extremely short (can't remember the time off the top of my head). quarters would only be 10 minutes instead of 12. in college, you get 5 fouls for 40 minutes of game time, 1 per every 8 minutes. what’s your day rate. I'll assume you mean how much actual time would be served on a particular sentence... it starts with "good time credits" that are applied to the sentence calculator a the beginning of the sentence. An inmate can only lose that good time by having behavior issues or breaking numerous rules. In federal you get 15%, state prison ranges from 15-30% good time. The difference with the state is that they're also dealing with a parole system too that can release an offender having done only one-third of their sentence. juniors. college students are classified the same as high school students. 1st year are freshman. 2nd year are sophomores. 3rd year are juniors, and 4th year are seniors. A. It’s difficult to assess the seriousness of this on the basis of only a letter so let me just share a couple of thoughts.

People by nature tend to fall somewhere on a scale from introvert to extrovert. It may be that at least part of this is that you are on the introvert end of the scale. There is nothing wrong with that! But, the larger culture celebrates extroverts. In high school, the general idea is that everyone is supposed to be outgoing and popular. Of course, not everyone can be. Not everyone wants to be. So let’s at least assume that part of what goes on is that you have a more restrained approach to life. One thing that supports this is that you do have a couple of close friends and that seems to be enough for you.

As for being out with others: I wonder if you have developed the skills you need to be comfortable out in the social world. Introverts can and do learn how to manage social situations enough so that they can be successful in their careers and can find loving relationships. Notice that I said “skills”. Skills are behaviors you can learn (like how to make small talk, how to be an active listener, how to be a good communicator, etc.). As you get more practiced in these skills, you will be more comfortable being with people for longer periods of time. But you will still need your alone time to “recover” from a lot of social interaction.

The line in your letter that does worry me is your statement that you can spend hours holed up in your room and in bed. Yes, you may need time to recharge your social batteries but it would do a lot more for your self-esteem if you would use that time to pursue an interest or to do something to make the world a better place. Think about ways to support a cause or candidate or to educate yourself about something you are genuinely interested in. You will feel better about yourself than if you just hang out wondering if there is something wrong with you. An important bonus is that it will give you more to talk about when you are with people.

I hope this is helpful. I wish you well.  
 Dr. Marie

I Want or Need to Be Alone class intervals
frequency
(fi)
xi
di = xi - a
fi di


0 - 20
17
10
-40
-680


20 - 40
28
30
-20
-560


40 - 60
32
50 = a
0
0


60 - 80
p
70
20
20p


80 - 100
19
90
40
760


total
Î£
fi = 96 + p


Î£ fi di = 20p -
480


![](https://s3mn%20mnimgs%20com/img/shared/discuss_editlive/5130830/2013_07_08_13_01_36/mathmlequation8813644107607516415%20png) one doesn't substitute for the other; they are two very different things. so, if there's time for both, why not have both? the relationship of wavelength and frequency will appear as:using the wavelength range given, 280-320 nm, frequency range will be calculated using the equation above and by converting the values to the proper units [readmore]each wavelength must be in meters:we need to calculate the frequency for both 280 and 320 nm:range of frequency will appear as 1.07x1015 to 9.38x1014 s-1