Bar and histogram plots in MATLAB - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of Bar Plot with Custom Colors

What will be the color of the bars in the following MATLAB code?

MATLAB

y = [5 10 15];
bar(y, 'FaceColor', [0 0.5 0]);

A Bars will be red

B Bars will be green with RGB [0 0.5 0]

C Bars will be blue

D Bars will be black

💡 Hint

FaceColor property sets the bar color using RGB values between 0 and 1.

The FaceColor property is set to [0 0.5 0], which means no red, half green, no blue, resulting in a medium green color.

❓ Predict Output

intermediate

Histogram Bin Count Output

What is the output of the following MATLAB code?

MATLAB

data = [1 2 2 3 4 4 4 5];
h = histogram(data, 4);
disp(h.BinCounts);

A [1 2 1 4]

B [1 2 3 2]

C [2 3 2 1]

D [1 3 2 2]

💡 Hint

Bins are automatically spaced to cover the data range with 4 bins.

The data range is from 1 to 5. With 4 bins, the bins cover intervals [1-2), [2-3), [3-4), [4-5]. Counting values in each bin gives [1 2 1 4].

🔧 Debug

advanced

Fix the Error in Bar Plot Code

The following MATLAB code produces an error. Which option fixes it so the bar plot shows correctly?

MATLAB

x = [1 2 3];
y = [4 5];
bar(x, y);

A Change y to have 3 elements: y = [4 5 6];

B Use bar(y) without x: bar(y);

C Change x to have 2 elements: x = [1 2];

D Transpose y: bar(x, y');

💡 Hint

x and y vectors must have the same length for bar(x,y).

The error occurs because x and y have different lengths. Making y length 3 matches x and fixes the error.

📝 Syntax

advanced

Identify Syntax Error in Histogram Code

Which option contains a syntax error in MATLAB histogram plotting?

A histogram(data, 10);

B histogram(data, 'BinWidth', 0.5);

C histogram(data, 'Normalization', 'probability');

D histogram(data, BinWidth=0.5);

💡 Hint

MATLAB uses name-value pairs with quotes, not equal signs.

Option D uses an equal sign (=) which is invalid syntax for name-value pairs in MATLAB. Correct syntax uses comma and quotes.

🚀 Application

expert

Number of Bars in Grouped Bar Plot

Given the following MATLAB code, how many bars will be displayed in the plot?

MATLAB

data = [3 5 2; 4 6 1];
bar(data, 'grouped');

A 2 bars

B 3 bars

C 6 bars

D 9 bars

💡 Hint

Each row is a group, each column is a bar within the group.

The data matrix has 2 rows and 3 columns. Grouped bar plot shows 3 bars per group, 2 groups total, so 6 bars.