Matplotlib error conditional bar subplot yerr

# coding: utf-8


get_ipython().magic('matplotlib notebook')
import pandas as pd
import numpy as np
import math   # This will import math module
import matplotlib.pyplot as plt
import matplotlib.gridspec as gridspec

#Ask for the value of interest
Value = int(input('what value do you want to test? '))


# Data formed list wise
np.random.seed(12345)

d1992 =np.random.normal(32000,2000,3650)
d1993 =np.random.normal(43000,3500,3650)
d1994 =np.random.normal(43500,2400,3650)
d1995 = np.random.normal(48000,1700,3650)
df = pd.DataFrame({1992:d1992,
                   1993:d1993,
                   1994:d1994,
                   1995:d1995})
              
labels = df.columns

fig, ax = plt.subplots()

# colorise conditionally 
interval =pd.DataFrame()
interval['mean']=df.mean()
interval['std']=df.std()*1.96
interval['high']= df.mean()+df.std()*1.96
interval['low'] = df.mean()-df.std()*1.96
interval['value']=Value

conditions = [
    (interval['high']<interval['value']),
    (interval['low']>interval['value'])]
choices = ['blue', 'red']
interval['colour'] = np.select(conditions, choices, default='skyblue')

# set the x axis with width
ind = np.arange(4)  # the x locations for the groups
width = 0.5       # the width of the bars


# Draw the bars
ax.bar(ind+width, interval['mean'], color=interval['colour'], yerr =interval['std'] , capsize=10, align='center')


# copy the axes of the main plot onto the line and box plots

ax3 = ax.twinx()
ax3.set_ylim(ax.get_ylim())


# Draw the line
ax3.plot([0, 4], [Value, Value], color='g', linestyle='-', linewidth=2)

#labels
ax.set_xticks(ind+width)
ax.set_xticklabels(labels, rotation='horizontal')

plt.show()