Chapter 9 Hypothesis Testing With One Sample Question 1-10

Chapter 9 Hypothesis Testing With One Samplequestion 1 10 Pointswri

Write a method that computes the average of the values in an array of doubles. The header of the method is as follows: public static double average(double[] x)

Write a complete Java class that will create a 2D array of randomly generated ints with dimensions of 5 rows and 10 columns. Print the values of each cell to a 5x10 table.

You have an int array named examScores that is 1000 elements in length. Provide a single line of code that would sort the examScores.

You have an int array named examScore that is 100 elements in length. Provide a single line of code that would search the examScores for values that are 50.

Describe an application that would be a good choice for using 3D array. Provide the size of the array and the most likely data type. Provide the specific Java nested loop you would use to populate the array elements with random values.

Sample Paper For Above instruction

Chapter 9 Hypothesis Testing With One Samplequestion 1 10 Pointswri

Java Programming and Array Applications: Combining Method Implementation and Array Operations

Introduction

Java programming provides fundamental constructs like methods, arrays, and loops that are essential for computational tasks. Efficient manipulation of data structures enables developers to perform various operations such as calculating averages, creating and printing multi-dimensional arrays, sorting, and searching. Additionally, understanding how to visualize complex data with multi-dimensional arrays enhances the development of applications like simulations and modeling. In this paper, we will explore a variety of programming tasks: implementing an average calculation method, creating a 2D array with random values, sorting an array, searching within an array, and designing a 3D array application.

Implementing a Method to Compute the Average of Doubles

The first task involves developing a method that calculates the average of values stored in a double array. The method must accept an array of doubles and return their mean. Here's the specific implementation:

```java

public static double average(double[] x) {

double sum = 0.0;

for (double value : x) {

sum += value;

}

return (x.length == 0) ? 0 : sum / x.length;

}

```

This method initializes a sum variable, iterates through each element using an enhanced for loop, adds each value to the sum, and finally computes the average by dividing the total sum by the number of elements. It also handles the edge case where the array length is zero to avoid a division by zero error.

Creating and Printing a 2D Array of Random Integers

The second task is to develop a complete Java class that initializes a two-dimensional array with 5 rows and 10 columns, populates it with randomly generated integers, and prints the array in a formatted table.

```java

import java.util.Random;

public class Random2DArray {

public static void main(String[] args) {

int[][] array = new int[5][10];

Random rand = new Random();

// Populate array with random integers and print in table format

for (int i = 0; i

for (int j = 0; j

array[i][j] = rand.nextInt(100); // Random ints between 0 and 99

System.out.printf("%4d", array[i][j]);

}

System.out.println();

}

}

}

```

This class, `Random2DArray`, creates a 5x10 matrix, fills each cell with a random number between 0 and 99, and prints the contents row by row with formatted output, aligning columns for clarity.

Sorting an Array of Exam Scores

Given an integer array `examScores` with 1000 elements, sorting involves invoking the built-in `Arrays.sort()` method. The required single line of code is:

```java

Arrays.sort(examScores);

```

This statement sorts the `examScores` array in ascending order efficiently and is part of Java's standard library.

Searching for a Specific Value in an Array

To find occurrences of the value 50 within an array `examScores` of length 100, the most straightforward single line (assuming appropriate context) is to use a loop if not searching with built-in methods. However, for the purpose of this task, a comprehension example would be:

```java

for (int score : examScores) if (score == 50) System.out.println("Found 50");

```

Alternatively, to locate the index of value 50, one might write:

```java

int index = -1; for (int i = 0; i

```

But the key concept is utilizing a loop or `Arrays.binarySearch()` if array is sorted.

Designing a 3D Array Application

A typical application for a 3D array is modeling a voxel-based 3D environment, such as in medical imaging (MRI scans) or game development. For example, creating a 10x10x10 grid of voxels where each voxel stores a boolean indicating active/inactive status or an integer representing tissue density.

The Java array size could be:

```java

int[][][] voxelGrid = new int[10][10][10];

```

The data type is most likely `int` for density values.

To populate the array with random density values using nested loops:

```java

import java.util.Random;

Random rand = new Random();

for (int i = 0; i

for (int j = 0; j

for (int k = 0; k

voxelGrid[i][j][k] = rand.nextInt(256); // Density between 0-255

}

}

}

```

This triple-nested loop accesses each voxel to assign a random density, simulating varied tissue types or material densities.

Conclusion

Proficiency in Java arrays and methods enables developers to perform fundamental operations essential for data analysis, visualization, and simulation. Implementing functions like averaging, integrating array creation and display, sorting, and searching are building blocks for more complex applications. Designing multi-dimensional arrays extends these capabilities to model real-world phenomena, including 3D environments and medical imaging data. Mastery of these techniques improves problem-solving efficiency and supports the development of robust Java applications.

References

  • Oracle Java Documentation. (2023). Arrays. https://docs.oracle.com/javase/tutorial/java/nutsandbolts/arrays.html
  • Deitel, P. J., & Deitel, H. M. (2014). Java: How to Program (10th ed.). Pearson Education.
  • Bloch, J. (2008). Effective Java (2nd ed.). Addison-Wesley.
  • Eckel, B. (2006). Thinking in Java (4th ed.). Pearson Education.
  • Lippman, R., Lajoie, J., & Moo, R. (2012). C++ Primer (5th ed.). Addison-Wesley.
  • Data Structures and Algorithms in Java. (2021). Robert Lafore. Pearson.
  • Java Platform SE Documentation. (2023). Arrays and Collections. https://docs.oracle.com/en/java/javase/
  • Sun Microsystems. (1995). Java Language Specification. https://docs.oracle.com/javase/specs/
  • Szumlanski, M. (2014). Java Programming: From Problem Analysis to Program Design. Cengage Learning.
  • Hann, C. E. (2007). Introduction to Mathematical Programming with Java. World Scientific Publishing.

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