Standard deviation

#1
Hi, I'm trying to calculate the standard deviation of a dataset for my uni meta analysis from this formula. How would I go about calculating the inverse of phi Φ? Would I just substitute 1.618033 which is what the value of phi is according to google?
sd.PNG
 
#2
Hi, I'm trying to calculate the standard deviation of a dataset for my uni meta analysis from this formula. How would I go about calculating the inverse of phi Φ? Would I just substitute 1.618033 which is what the value of phi is according to google?
View attachment 4083
Also b = minimum value of range
a = maximum value
n = number of participants
 

hlsmith

Less is more. Stay pure. Stay poor.
#3
Curious where you are getting this formula from. Can you provide a link, so we can see how it was presented. I am not imagining phi is a constant or irrational number you are supposed to input, I feel like it may be derived from your data.
 

hlsmith

Less is more. Stay pure. Stay poor.
#4
perhaps feed bracket data into norminv distribution? But if you provided content info that would help.
 

hlsmith

Less is more. Stay pure. Stay poor.
#5
?
Φ symbol represents the cumulative distribution function (CDF) of a standard normal distribution, Φ(z). In R, the CDF of the standard normal distribution is implemented in the pnorm function. But you may want the inverse. But I could be making stuff up here :)
 
#7
?
Φ symbol represents the cumulative distribution function (CDF) of a standard normal distribution, Φ(z). In R, the CDF of the standard normal distribution is implemented in the pnorm function. But you may want the inverse. But I could be making stuff up here :)
In the article they're using R but I have no idea how to use this or where to begin.
 

Dason

Ambassador to the humans
#8
?
Φ symbol represents the cumulative distribution function (CDF) of a standard normal distribution, Φ(z). In R, the CDF of the standard normal distribution is implemented in the pnorm function. But you may want the inverse. But I could be making stuff up here :)
No you're right. The formula requires the inverse of the cdf of the standard normal.
 

Dason

Ambassador to the humans
#10
You would input what's in the parenthesis into the function. But pnorm is the cdf of the normal and we want the inverse of that. It sounds like you're using R so use qnorm instead.
 
#11
You would input what's in the parenthesis into the function. But pnorm is the cdf of the normal and we want the inverse of that. It sounds like you're using R so use qnorm instead.
Okay so just to clarify I enter the values I get within the brackets into qnorm and multiply by 2 I'll get the denominator?