9. If X is a normally distributed random variable
with mean μ = 5 and standard deviation
, then find the transformation which maps the curve of the
density function of X, f(x), to the curve of the standard normal distribution.
![]()
7. Suppose a continuous random variable X has probability density function:
![]()
,Which of
the following graphs represents this function?
8 The time it takes Geoff to complete a crossword puzzle is normally distributed with a mean of 1 hour and a standard deviation of 12 minutes. On 10% of occasions he is able to complete the crossword in k minutes or less. Find the value of k to the nearest whole number.
6. If the scores for a VCE subject are normally distributed with a mean of 30 and a standard
deviation of 7, then approximately 68% of students score between.
5. If the length of time a certain battery will last in a graphics calculator is normally distributed with a mean of 40 hours and a standard deviation of 4.6 hours, then find the percentage of batteries which will last more than 50 hours.
4. The random variable X has a normal distribution with mean 7.2 and standard deviation 1.44. If Z is a standard normal random variable then the probability that X is more than 3.6 is
A Pr(Z < 2.5) B Pr(Z > 2.5) C 1 -Pr(Z < 2.5) D 1-Pr(Z > -2.5) E Pr(-2 < Z < 2)
3.If Z is a standard normal random variable, and Pr(Z > c) = 0.75, then find the value of c to 4 decimal place.
2.If Z is a standard normal
random variable,find the
to 4 decimal
place.
1.The
diagram below shows the graphs of two normal distributions with means
and
and standard deviations
1 and
respectively. Which of the following statements is true?
A. ![]()
B. ![]()
C. ![]()
D. ![]()
E. ![]()
(二)多个材料的叙述:列举排比、简短有力 采用列举的方式,一口气铺陈若干个事例,形成流泻奔腾的气势,这成为高考作文常用手法。
忙是省略号。四季在有规律地进行着冷暧交替,大自然就一直按照这样的规律不停地忙,为目标而不停地忙,让这种忙一直忙下去,当目标已达成,那么再找一个目标,继续这种忙,就开历史的长卷,我们看见牛顿在忙着他的实验;爱迪生在忙着思考;徐霞客在忙着记载游玩;李时珍在忙着编写《本草纲目》;再看那位以笔为刀和枪在不停地奋斗。忙是省略号,确定了一个目标那么就一直忙下去吧!这样的忙一定会忙出生命动的色彩。 忙是惊叹号、世界上的人都在忙着自己的事,蜜蜂以蜂蜜为回报,那么人呢?居里夫人的忙,以放射性元素的发现而得到了圆满的休止符;爱因斯坦的忙,以相对论的问世而画上了惊叹号;李白的忙,以那豪放的诗歌而有了很大的成功;张的忙,因为那地动仪的出世而让世人得以仰慕。每个人都应该有效率地忙,而不是整天碌碌无为地白忙。人生是有限的、短暂的,因此,每个人都应该在有限的生命里忙出他人生的精彩篇章。
上海考生作文《忙,不亦乐乎》
这两段都是事例排比的方式,使材料更丰富,内容更充实。
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