title: ValueError: Wrong number of items passed 500, placement implies 1, Python and Pandas
body: <p>I'm importing just two columns from .xlsx file and I would like to calculate some stuff (mean, deviation, percent change) and then I would like to plot all this. First part doesn't give me any problems, but plotting does.</p>
  
  <p>My code looks like this:</p>
  
  <pre><code>import matplotlib.pyplot as plt
  import numpy as np
  import pandas as pd
  import matplotlib.mlab as mlab
  import math
  
  df = pd.read_excel('KDPrviIzbor.xlsx', sheetname='List1', index_col = 0)
  ch = df.pct_change(periods=252)
  
  ma = np.mean(ch)*100
  std = np.std(ch)*100
  
  x = np.linspace(-100,100,500)
  plt.plot(x,mlab.normpdf(x,ma,std))
  
  plt.show()
  </code></pre>
  
  <p>But when I run my code, I get this error:</p>
  
  <pre><code>Traceback (most recent call last):
  File "C:/Users/David/PythonStuff/normal_distribution.py", line 21, in &lt;module&gt; plt.plot(x,mlab.normpdf(x,ma,std))
  File "C:\Python27\lib\site-packages\matplotlib\mlab.py", line 1579, in normpdf return 1./(np.sqrt(2*np.pi)*sigma)*np.exp(-0.5 * (1./sigma*(x - mu))**2)
  File "C:\Python27\lib\site-packages\pandas\core\ops.py", line 534, in wrapper dtype=dtype)
  File "C:\Python27\lib\site-packages\pandas\core\series.py", line 220, in __init__ data = SingleBlockManager(data, index, fastpath=True)
  File "C:\Python27\lib\site-packages\pandas\core\internals.py", line 3383, in __init__ ndim=1, fastpath=True)
  File "C:\Python27\lib\site-packages\pandas\core\internals.py", line 2101, in make_block placement=placement)
  File "C:\Python27\lib\site-packages\pandas\core\internals.py", line 77, in __init__ len(self.values), len(self.mgr_locs)))
  ValueError: Wrong number of items passed 500, placement implies 1`
  </code></pre>
  
  <p>I figured that the problem is in:</p>
  
  <p><code>plt.plot(x,mlab.normpdf(x,ma,std))</code></p>
  
  <p>but I cannot solve it. Any suggestions? </p>