Top Posters
Since Sunday
n
3
j
3
x
2
c
2
2
p
2
n
2
3
2
C
2
z
2
k
2
d
2
Home Q & A Board Biology-Related Homework Help Zoology and Botany (Moderator: ehd123)
New Topic  
foofighter15 foofighter15
wrote...
Go to Answer
Posts: 21
Rep: 0 0
10 years ago
My biology experiment is on the mean day of germination in seeds.

Would a  high standard deviation indicate high variability in data? What might cause the data to be highly variable? Could confounding variables increase the variability? Does having a high variability mean that my data is not reliable?

Thanks for helping, in advance =]
Read 228 times
2 Replies
Replies
wrote...
#1
10 years ago
A higher than expected standard deviation indicates you have more variability in your observed data than expected. This may mean the data is genuinely more variable than you thought, or it could be due to one or more outliers as a single outlying value will shift the mean and substantially increase the standard deviation. To give an example, if you planted 10 seeds and 9 of them germinated between 12 and 16 days later, but one failed to germinate so you recorded it as 30 days (maximum length of the experiment) then not only would this '30 day' seed inflate the mean days till germination but it would even more inflate the variability in germination dates.  Check to see if you have an outlier and, if so, think about whether you have good reason to fairly eliminated this from your data. However note that the fact of being an outlier is not in and of itself good reason - you need to be able to explain why it was an outlier in order to explain why eliminating it is justified.
Answer accepted by topic starter
michaelavammichaelavam
wrote...
#2
Posts: 18
Rep: 0 0
10 years ago
Sign in or Sign up in seconds to unlock everything for free
This verified answer contains over 110 words.
1

Related Topics
New Topic      
Quick Reply
Explore
Post your homework questions and get free online help from our incredible volunteers
  724 People Browsing
Start New Topic Take the Tour CoursesNew Study Tools Topics Trending Browse by Textbook
Live Chat
Related Images
  
 4432
  
 1532
  
 44
Your Opinion
What's your favorite funny biology word?
Votes: 329
Previous poll results: Which industry do you think artificial intelligence (AI) will impact the most?