Question 332582
Since you dont have the exact value, but instead have a range of values
the first thing to do is to get a surrogate (proxy) value.  This is usually set a the mid point of the interval

1.5
3.5
etc...
---
next set up a data table as follows

Let X=midpoint, F=frequency
--
  X ------   F ----  X*F    
1.5 -----   9 ----  13.5
3.5 ----- 22  ----  77.0
5.5 ----- 28  ---- 154.0
7.5 ----- 15  ---- 112.5
9.5 ----- 14  ---- 133.0        
---
Compute the average = Xbar = {{{sum(Xi*Fi)/sum(Fi)=490/88=5.57}}}
--
for each interval compute a column (Xi-Xbar)^2
and then sum this column
{{{sum((Xi-Xbar)^2)*Fi}}} =[(1.5-5.57)^2]*9 + [(3.5-5.57)^2]*22 +..+[(9.5-5.57)^2]*14 = 515.59

this sum represents the sum of squared deviations.
---
Find the Variance
Variance = {{{sum((Xi-Xbar)^2)*Fi/(sum(Fi)-1)}}}=515.59/(88-1)=5.926
---
Standard dev = Sqrt(Variance) = Sqrt(5.926)=2.434

===
There is another form of the variance formula that you could use


Variance = {{{(sum((Xi^2))*Fi - Xbar^2*sum(Fi))/(sum(Fi)-1)}}}