# Pre-lab Quiz: Chapter Three Summary Statistics (Fall) Answers

```Pre‐labQuiz:ChapterThreeSummaryStatistics(Fall)
Name: TeamNumber: Instructi ons: N o t ea m wo r k is a ll o w ed o n t h i s quiz.This quiz is duet o your coac h
a t t h e b eg in n i ng of t he c or r esp on d ing la bse s sion . Us e t h e la bmanu a la ndt h e
o n l in e co urs e t o h e lp yo u w it h you r a n swe rs . P l ea s es how yo ur wo rka nd w r it e
do wnt he Exc elcommands orfunct io ns that yo u us e.
1. What’s the fo rmula t o ca lc ulat e Pea rso n’s Seco nd Sk ewness Co eff ic ient for a sa mp le in Exc el?
Sk = 3* (AVERA G E(array )‐ M ED IA N ( a r ra y ) ) /S T D E V . S ( ar r ay )
2 / 3p ts
2. T /F , a nd e x p la i n :T h epo p ula t io nvaria nc e ofa c erta indata s et is 13. 6 4 b u t w h ent h e va r ianc e is ca lc u lat edas asa mp l ev ar ia nc e it is larg er,14.18.For
t h esa m e r easo n ,t h e pop u la t io nm ea n f or this dat a se t wi l l b esmallerthanthe
sa mp le m ean.
False. The formula for v ar ia nc eis di ffe rent fr om popu lation t o
s amp le ,but the formula f o rthem ea nis NO Tdi fferent. 2 / 3p ts
3. Whydo wesa yt hat the mod e r epo rt ed byt he Descript iveStat ist ics t oo l is not u s ef u l? The mode fo und inDes c ripti veStatis ti cs is the firs tm ode found, whi chis
fine i f the re is on ly one mod ein ad at a set, but it is ap ro b lemin amu lti ‐
m od a ld a ta s et. Un f or tu na te ly ,y ou cannot te ll from the ou tpu tw h i ch
p a rti cu l a rsi tu ati on your d at a se tis in.
2 / 3p ts
```